Add recommended files for community support & update CONTRIBUTING.md (#6898)

* Add ./github/SECURITY.md

Per GitHub best practices, this give people instructions for reporting
security vulnerabilities in this project.

* Add SUPPORT.md file

SUPPORT.md files are another GitHub best practice; they're used to to
let people know about ways to get help with a project.

* Add CITATION.cff file

[`CITATION.cff`](https://citation-file-format.github.io/) files are
plain text files with human- and machine-readable citation information
for software. Code developers can include them in their repositories
to let others know how to correctly cite their software. GitHub
supports them, and uses `CITATION.cff` files to automatically produce
citation metadata records for the "Cite this repository" button on a
repository's front page.

* Make small corrections & enhancements to CONTRIBUTING.md

This contains a variety of small changes:
- capitalization fixes (e.g., cirq → Cirq)
- clarifications
- links to more information

* Update CITATION.cff

Correction to capitalization.

* Fixes for CONTRIBUTING.md issues raised during code review

Author: mhucka

.github/SECURITY.md

@@ -0,0 +1,30 @@
+# Reporting security issues
+
+The Cirq developers and community take security bugs in Cirq seriously. We
+appreciate your efforts to responsibly disclose your findings, and will make
+every effort to acknowledge your contributions.
+
+Please **do not** use GitHub issues to report security vulnerabilities; GitHub
+issues are public, and doing so could allow someone to exploit the information
+before the problem can be addressed. Instead, please use the GitHub ["Report
+a Vulnerability"](https://github.com/quantumlib/cirq/security/advisories/new)
+interface from the _Security_ tab of the Cirq repository.
+
+Please security bugs in third-party modules to the person or team maintaining
+the module rather than the Cirq project stewards, unless you believe that some
+action needs to be taken with Cirq in order to guard against the effects of a
+security vulnerability in a third-party module.
+
+## Responses to security reports
+
+The project stewards at Google Quantum AI will send a response indicating the
+next steps in handling your report. After the initial reply to your report, the
+project stewards will keep you informed of the progress towards a fix and full
+announcement, and may ask for additional information or guidance.
+
+## Additional points of contact
+
+Please contact the project stewards at Google Quantum AI via email at
+[email protected] if you have questions or other concerns. If
+for any reason you are uncomfortable reaching out to the project stewards,
+please email [email protected].

CITATION.cff

@@ -0,0 +1,32 @@
+cff-version: 1.2.0
+message: If you use this software, please cite it as below.
+authors:
+  - name: Cirq Developers
+    website: https://github.com/quantumlib/Cirq/graphs/contributors
+title: Cirq
+abstract: Python package for writing, manipulating, and running quantum circuits on quantum computers and simulators.
+version: 1.4.1
+date-released: 2024-06-26
+url: https://quantumai.google/cirq
+repository-code: https://github.com/quantumlib/Cirq
+license: Apache-2.0
+identifiers:
+  - type: doi
+    value: 10.5281/zenodo.4062499
+    description: Archival DOI for Cirq software releases.
+type: software
+keywords:
+  - api
+  - nisq
+  - noisy intermediate-scale quantum
+  - python
+  - quantum algorithms
+  - quantum circuit simulation
+  - quantum circuits
+  - quantum computing
+  - quantum programming
+  - quantum programming languages
+  - quantum simulation
+  - sdk
+  - simulation
+  - software

CONTRIBUTING.md

@@ -5,14 +5,15 @@ We do have some guidelines to follow, covered in this document, but don't
 worry about (or expect to) get everything right the first time!
 Create a pull request and we'll nudge you in the right direction. Please also
 note that we have a [code of conduct](CODE_OF_CONDUCT.md) to make Cirq an
-open and welcoming environment.
+open and welcoming community environment.
 
 ## Contributor License Agreement
 
-Contributions to this project must be accompanied by a Contributor License
-Agreement. You (or your employer) retain the copyright to your contribution;
+Contributions to this project must be accompanied by a [Contributor License
+Agreement](https://cla.developers.google.com/about) (CLA). You
+(or your employer) retain the copyright to your contribution;
 this simply gives us permission to use and redistribute your contributions as
-part of the project. Head over to <https://cla.developers.google.com/> to see
+part of the project. Head over to https://cla.developers.google.com/ to see
 your current agreements on file or to sign a new one.
 
 You generally only need to submit a CLA once, so if you've already submitted one
@@ -26,27 +27,28 @@ use GitHub pull requests for this purpose.
 [GitHub Help](https://help.github.com/articles/about-pull-requests/) has
 information on using pull requests.
 
-The preferred manner for submitting pull requests is for users to fork
-the Cirq [repo](https://github.com/quantumlib/Cirq) and then use a
-branch from this fork to create a pull request to the main Cirq repo.
-
-The basic process for setting up a fork is
-1. Fork the Cirq repo (Fork button in upper right corner of
-[repo page](https://github.com/quantumlib/Cirq)).
-Forking creates a new github repo at the location
-```https://github.com/USERNAME/cirq``` where ```USERNAME``` is
-your github id. Use the directions on the
+The preferred manner for submitting pull requests is for developers to fork
+the Cirq [repository](https://github.com/quantumlib/Cirq) and then use a [git
+branch](https://git-scm.com/book/en/v2/Git-Branching-Branches-in-a-Nutshell)
+from this fork to create a pull request to the main Cirq repo. The basic process for setting
+up a fork is as follows:
+
+1. Fork the Cirq repository (you can use the _Fork_ button in upper right
+corner of the [repository page](https://github.com/quantumlib/Cirq)).
+Forking creates a new GitHub repo at the location
+`https://github.com/USERNAME/Cirq`, where `USERNAME` is
+your GitHub user name. Use the instructions on the
 [development page](docs/dev/development.md) to download a copy to
 your local machine. You need only do this once.
-1. Checkout main and create a new branch from this main
+1. Check out the `main` branch and create a new branch from `main`:
     ```shell
     git checkout main -b new_branch_name
     ```
-    where ```new_branch_name``` is the name of your new branch.
+    where `new_branch_name` is the name of your new branch.
 1. Do your work and commit your changes to this branch.
-1. If you have drifted out of sync with the main from the
-main cirq repo you may need to merge in changes.  To do this,
-first update your local main and then merge the local main
+1. If your local copy has drifted out of sync with the `main` branch of the
+main Cirq repo, you may need to merge in the latest changes.  To do this,
+first update your local `main` and then merge your local `main`
 into your branch:
     ```shell
     # Track the upstream repo (if your local repo hasn't):
@@ -60,70 +62,74 @@ into your branch:
     git checkout new_branch_name
     git merge main
     ```
-    You may need to fix merge conflicts for both of these merge
-    commands.
-1. Finally, push your change to your clone
+    You may need to fix [merge conflicts](
+    https://docs.github.com/articles/about-merge-conflicts)
+    during one or both of these merge processes.
+1. Finally, push your changes to your forked copy of the Cirq repo on GitHub:
     ```shell
     git push origin new_branch_name
     ```
-1. Now when you navigate to the cirq page on github,
-[https://github.com/quantumlib/cirq](https://github.com/quantumlib/cirq)
+1. Now when you navigate to the Cirq repository on GitHub
+(https://github.com/quantumlib/Cirq),
 you should see the option to create a new pull request from
-your clone repository.  Alternatively you can create the pull request
+your clone repository.  Alternatively, you can create the pull request
 by navigating to the "Pull requests" tab in the page, and selecting
 the appropriate branches.
-1. The reviewer will comment on your code and may ask for changes,
-you can perform these locally, and then push the new commit following
-the same process as above.
+1. A reviewer will comment on your code and may ask for changes.
+You can perform the necessary changes locally, and then push the new commit
+following the same process as above.
 
 ## Development Environment Setup
 
-Please refer to our [development page](docs/dev/development.md) for instructions
-on setting up your local development environment.
+Please refer to our [development page](docs/dev/development.md) for
+instructions on setting up your local development environment.
 
 ## Code Testing Standards
 
 When a pull request is created or updated, various automatic checks will
-run to ensure that the change won't break Cirq and meets our coding standards.
+run on GitHub to ensure that the changes won't break Cirq, as well as to make
+sure they meet the Cirq project's coding standards.
 
-Cirq contains a continuous integration tool to verify testing.  See our
+Cirq includes a continuous integration tool to perform testing.  See our
 [development page](docs/dev/development.md) on how to run the continuous
 integration checks locally.
 
-Please be aware of the following code standards that will be applied to any
+Please be aware of the following coding standards that will be applied to any
 new changes.
 
 - **Tests**.
 Existing tests must continue to pass (or be updated) when new changes are
-introduced. We use [pytest](https://docs.pytest.org/en/latest/) to run our
+introduced. We use [pytest](https://docs.pytest.org) to run our
 tests.
 - **Coverage**.
 Code should be covered by tests.
-We use [pytest-cov](https://pytest-cov.readthedocs.io/en/latest/) to compute
+We use [pytest-cov](https://pytest-cov.readthedocs.io) to compute
 coverage, and custom tooling to filter down the output to only include new or
 changed code. We don't require 100% coverage, but any uncovered code must
 be annotated with `# pragma: no cover`. To ignore coverage of a single line,
 place `# pragma: no cover` at the end of the line. To ignore coverage for
 an entire block, start the block with a `# pragma: no cover` comment on its
 own line.
 - **Lint**.
-Code should meet common style standards for python and be free of error-prone
-constructs. We use [pylint](https://www.pylint.org/) to check for lint.
+Code should meet common style standards for Python and be free of error-prone
+constructs. We use [Pylint](https://www.pylint.org/) to check for code lint.
 To see which lint checks we enforce, see the
-[dev_tools/conf/.pylintrc](dev_tools/conf/.pylintrc) file. When pylint produces
-a false positive, it can be squashed with annotations like
-`# pylint: disable=unused-import`.
+[dev_tools/conf/.pylintrc](dev_tools/conf/.pylintrc) file. When Pylint produces
+a false positive, it can be silenced with annotations. For example, the
+annotation `# pylint: disable=unused-import` would silence a warning about
+an unused import.
 - **Types**.
 Code should have [type annotations](https://www.python.org/dev/peps/pep-0484/).
 We use [mypy](http://mypy-lang.org/) to check that type annotations are correct.
-When type checking produces a false positive, it can be ignored with
-annotations like `# type: ignore`.
+When type checking produces a false positive, it can be silenced with
+annotations such as `# type: ignore`.
 
 ## Request For Comment Process for New Major Features
 
-For larger contributions that will benefit from design reviews, please use the
+For larger contributions that will benefit from design reviews, please use the Cirq
 [Request for Comment](docs/dev/rfc_process.md) process.
 
 ## Developing notebooks
 
-Please refer to our [notebooks guide](docs/dev/notebooks.md) on how to develop iPython notebooks for documentation.
+Please refer to our [notebooks guide](docs/dev/notebooks.md) on how to develop
+iPython notebooks for documentation.

SUPPORT.md

@@ -0,0 +1,28 @@
+# Support
+
+Thank you for your interest in this project! If you are experiencing problems
+or have questions, the following are some suggestions for how to get help.
+
+> [!NOTE]
+> Before participating in our community, please read our [code of
+> conduct](CODE_OF_CONDUCT.md). By interacting with this repository,
+> organization, or community, you agree to abide by its terms.
+
+## Report an issue or request a feature
+
+To report an issue or request a feature in Cirq, please first search the [issue
+tracker on GitHub](https://github.com/quantumlib/Cirq/issues) to check if there
+is already an open issue identical or similar to your bug report/feature
+request. If there is none, go ahead and file a new issue in the issue tracker.
+
+## Attend the developer meetings
+
+_Cirq Cynq_ is our biweekly virtual meeting of contributors to discuss
+everything from issues to ongoing efforts, as well as to ask questions. Join
+the [`cirq-dev` Google Group](https://groups.google.com/forum/#!forum/cirq-dev)
+to get an automatic meeting invitation.
+
+## Contact the maintainers
+
+For any questions or concerns not addressed here, please email
+[[email protected]](mailto:[email protected]).