CI: Test on newer Pythons; enable Python dev mode

[akx]

See https://docs.python.org/3.12/library/devmode.html#devmode for what PYTHONDEVMODE does.

[akx]

@PierreF Rebased, ready for review.

[cclauss]

Love the addition of PYTHONDEVMODE -- Cool!

[PierreF]

The PR looks fine, we just broke "python setup.py test" command.
I'm not sure whether is really used (I think the the release process, which might use use). Anyway, I'll have a look at #774 which should both cause few conflict with this PR and remove "setup.py" completely.

[cclauss]

https://setuptools.pypa.io/en/latest/deprecated/commands.html

running python setup.py directly as a script is considered deprecated.
This also means that users should avoid running commands directly via python setup.py <command>.

[akx]

Yeah, breaking setup.py test was on purpose – there's no reference to it anywhere in the repo (other than in the makefile), so I figured it wasn't really needed (anymore)... But yeah, #774 will get rid of setup.py altogether.

[PierreF]

Confirmed that setup.py is not used for release, at least not how I do release (which I should document somewhere).

My process is currently:

• testing by calling tox (inside a Docker image python:3.x)
• testing linter by calling tox
• tag & push tag
• build and upload to PyPi (using make upload)

Therefor this PR seems fine for me.

[akx]

My process is currently: ...

If it helps, the procedure I've built for python-babel is pretty slick these days – everything is done on GitHub Actions, and I just okay the release (via the release GHA environment requiring an accept gate). See https://github.com/python-babel/babel/blob/master/.github/workflows/ci.yml

[PierreF]

That true that making a release on CI is better than locally, as it ensure your local environment don't affect the release. I take not of your workflow and will consider it.