Set up GH Action for releases

[dmwyatt]

When the version is bumped with poetry version, we should automatically create a GH release and a PyPI release.

Actually, I think maybe it'd be better to do this when tagging with git? Use something like poetry-dynamic-versioning.

So when we want to do a new version something like this?

1. Make sure main has the commits we want to include in the release.
2. Use some tool to bump git tag version.
3. Something something for release notes.
4. Make GH release.
5. Make PyPI release.

Some links to investigate further:

https://github.com/softprops/action-gh-release
https://keepachangelog.com/en/1.0.0/