Use importlib.metadata instead of pkg_resources

[jnns]

pkg_resources is deprecated and emits warning messages.

Fixes #131

[adamchainz]

Thanks for working on this.

I would vote for dropping the __version__ attribute. Users who need the version can use importlib.metadata themselves. For the rest of us, loading and parsing it just wastes startup time.

Some data: I removed the __version__ attributes from ~20 packages in 2019, referring to importlib.metadata instead, e.g. https://github.com/adamchainz/apig-wsgi/blob/main/CHANGELOG.rst#240-2019-11-15 . I saw no complaints.

[jnns]

Thank you, Adam. I like your suggestion of removing __version__ and will adapt the pull request accordingly

[adamchainz]

Fix some typos, and remove the backport link, since nearly everyone runs Python 3.8+ now, and 3.7 is EOL in a couple months.

Suggested change

	* Removed usage of pkg_resource to avoid derecation
	warnings. If you want to inspect the installed version,
	use ``importlib.metadata.version("django-widget-tweaks")``
	(`docs <https://docs.python.org/3.8/library/importlib.metadata.html#distribution-versions>`__ /
	`backport <https://pypi.org/project/importlib-metadata/>`__).
	* Removed usage of ``pkg_resources`` to avoid deprecation
	warnings. If you want to inspect the installed version,
	use ``importlib.metadata.version("django-widget-tweaks")``
	(`docs <https://docs.python.org/3/library/importlib.metadata.html#distribution-versions>`__).

[georgek]

Agreed. 3.7 is now EOL. But we should stop testing on it too. Similar for old EOL Django versions like 2.2. Is there a policy regarding support for old versions?

[deeprave]

+1

I recently started using Rye as my project manager - it does not install nor use pip so there is none of its vendored dependencies either including pkg_resources. setuptools is not explicitly listed as a dependency, so consequently importing this module fails.

[deeprave]

Probably shouldn't remove version as it appears to be used by setup.py.

While setup.py is also deprecated, short of a larger change to convert to pyproject, in the meantime, importlib needs to be used (and works fine, tested locally). I will submit the alternative as a PR. Performance impact is pretty low given that python only imports a module once.

I also think it's poor practice to submit commented out code, but that is just IMHO :-)

[georgek]

Closed in favour of #135 as I don't see point of removing __version__. Also did remove 3.7 support.