Add workflow to publish python package

[jtraglia]

This PR adds a new workflow which publishes the python module to PyPI.

Marking this as a draft until devops has added the API key to GitHub secrets.

@kclowes (from EF snake charmers team) requested this.

[jtraglia]

Okay, the API key should be in the repo's secrets now. Ready for review.

[jtraglia]

Hmm I'm going to convert this to use ciwheelhouse which should simplify things a bit.

[kclowes]

This looks good to me @jtraglia. Thank you! I'm getting a deprecation warning from using python3 setup.py install here, but I did verify it's working! When I swapped that line locally with python -m build (the newer syntax), I was getting a clang error and haven't had time to debug. I can dig in more on Monday if you want, but it's just a deprecation warning so I think this is good to merge as-is. /cc @fselmo

[jtraglia]

Hey @kclowes, thanks for the review! I think I'm okay with a deprecation warning.

I'll plan to merge this on Monday & make a new release to test it soon after.