Remove Python 3.9 from workflow matrix

[auvipy]

EOL in october....

[browniebroke]

We should probably also update all the package metadata and docs?

[auvipy]

yes, thats why it is draft for now.

[browniebroke]

We should also remove unused targets from the tox.ini file

[peterthomassen]

I'm not familiar in what way these extra targets are special so that they should only run with the oldest support version. Why is that?

[browniebroke]

they should only run with the oldest support version. Why is that?

Hum... I'm actually not sure it matters. I said that because that seemed like how they were setup and it's probably where we're most likely to break something, but it's just a gut feeling.

A theorical example that comes to mind would be removal of an optional dependency because it's now part of the std lib (pytz/zoneinfo). We could have some tests break on older Python versions where ZoneInfo wouldn't be supported if we forgot about it... The base job might have caught such issue: running on the older Python without the optional dep.

django-rest-framework/tox.ini

Lines 28 to 32 in 0f57622

	[testenv:base]
	; Ensure optional dependencies are not required
	deps =
	django
	-rrequirements/requirements-testing.txt

Seems like the dist job treats some warnings as errors:

django-rest-framework/tox.ini

Lines 34 to 39 in 0f57622

	[testenv:dist]
	commands = python -W error::DeprecationWarning -W error::PendingDeprecationWarning runtests.py --no-pkgroot --staticfiles {posargs}
	deps =
	django
	-rrequirements/requirements-testing.txt
	-rrequirements/requirements-optionals.txt

So maybe this one should actually run on the most recent Python?

[browniebroke]

According to https://endoflife.date/python, EOL is at the end of the month. However, I'm happy to merge this already so it goes in the next release. Looks good to go from my perspective, unless there are any objections from other maintainers?