Partially revert #8042 and add CI in order to allow Python 3.12 support.

[WilliamJamieson]

Resolves JP-nnnn

Closes #8044

This PR enables Python 3.12 support for JWST, the main issue preventing this was solved by #8033.

Checklist for maintainers

• added entry in CHANGES.rst within the relevant release section
• updated or added relevant tests
• updated relevant documentation
• added relevant milestone
• added relevant label(s)
• ran regression tests, post a link to the Jenkins job below.
  How to run regression tests on a PR
• Make sure the JIRA ticket is resolved properly

[tapastro]

If/when/as this PR is merged, we can also revert #8057

[WilliamJamieson]

Looks like jwst still uses pkg_resources. I'll open a separate PR fixing that problem. The devdeps failure looks real, but due to numpy 2.0 problems.

[WilliamJamieson]

This requires #8095 in order to function properly as pkg_resources has been removed by Python 3.12.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (870f9de) 75.94% compared to head (2311764) 75.94%.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #8093   +/-   ##
=======================================
  Coverage   75.94%   75.94%           
=======================================
  Files         460      460           
  Lines       37625    37629    +4     
=======================================
+ Hits        28573    28577    +4     
  Misses       9052     9052           

Flag	Coverage Δ		*Carryforward flag
nightly	77.37% <ø> (ø)		Carriedforward from 870f9de

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[hbushouse]

So these various entries look to me like we're keeping tests using python 3.9 and 3.10, but getting rid of all tests using 3.11 and replacing them with 3.12? Why aren't we keeping any 3.11 tests?

[WilliamJamieson]

Line 72 runs the python 3.11 tests. If you would prefer I could just keep it Python 3.11 for the macos and stdevdeps jobs, only adding the additional py312-xdist job? I updated these because in the past we seem to have updated them to the latest version of python supported.

[hbushouse]

Given that we'll be delivering our next build under 3.11, I'd prefer to keep both the Linux and Macos entries using 3.11, but then use 3.12 for everything that involves latest/dev dependencies.

[WilliamJamieson]

Done, it now just adds a 3.12 linux job to the standard CI and changes the devdeps related jobs to 3.12

[hbushouse]

LGTM

[tapastro]

Merging this should maybe have prompted a build - the readme is now updated to imply support of python 3.12, but no release supports 3.12 yet.