Feature: suggest to user to add the pizza-action GitHub Action after generating a codeowners file

[nickytonline]

As a developer of the pizza CLI, I want to notify the user after generating a codeowners file that there is an OpenSauced pizza-action GitHub Action, so that the user can keep their codeowners file up to date in their repository.

[jpmcb]

The current flow is:

❯ pizza generate codeowners .
Finished processing commits for: /Users/jpmcb/workspace/opensauced/pizza-cli
Finished generating file: /Users/jpmcb/workspace/opensauced/pizza-cli/CODEOWNERS

Create an OpenSauced Contributor Insight to get metrics and insights on these codeowners:
$ pizza generate insight /Users/jpmcb/workspace/opensauced/pizza-cli

So, you're thinking something like this?

❯ pizza generate codeowners .
Finished processing commits for: /Users/jpmcb/workspace/opensauced/pizza-cli
Finished generating file: /Users/jpmcb/workspace/opensauced/pizza-cli/CODEOWNERS

Create an OpenSauced Contributor Insight to get metrics and insights on these codeowners:
$ pizza generate insight /Users/jpmcb/workspace/opensauced/pizza-cli

Generate codeowner files automatically in GitHub actions with pizza-action:
https://github.com/open-sauced/pizza-action

I like it.

But it might be abit wordy. And usually, people get pretty annoyed by this sort of thing in CLIs. We'll want to cautious about introducing these suggestions.