Add 3.12 to test matrix

[echedey-ls]

• [ ] Closes #xxxx
• I am familiar with the contributing guidelines
• [ ] Tests added
• [ ] Updates entries in docs/sphinx/source/reference for API changes.
• [ ] Adds description and name entries in the appropriate "what's new" file in docs/sphinx/source/whatsnew for all changes. Includes link to the GitHub Issue with :issue:`num` or this Pull Request with :pull:`num`. Includes contributor name and/or GitHub username (link with :ghuser:`user`).
• [ ] New code is fully documented. Includes numpydoc compliant docstrings, examples, and comments where necessary.
• Pull request is nearly complete and ready for detailed review.
• Maintainer: Appropriate GitHub Labels (including remote-data) and Milestone are assigned to the Pull Request and linked Issue.

I'm troubleshooting an error a user shared via google groups, #16
I can reproduce the error on Py3.12, and was wondering what the root cause is.

I think it also has something to do with versioneer.py, maybe, since it uses the removed distutils.

• Doesn't work with Python 3.12 python-versioneer/python-versioneer#375