Add Python 3.12 and limit MacOS/Window's tests.

[b-butler]

Description

Add Python 3.12 to CI testing and reduce non-Ubuntu runners to just oldest, minimal, and newest tests.

Motivation and Context

• Add newest Python version to testing.
• Reduce organization runners required for limited non-Linux OSes.

Checklist:

• I am familiar with the Contributing Guidelines.
• I agree with the terms of the Contributor Agreement.
• My name is on the list of contributors.
• The changes introduced by this pull request are covered by existing or newly introduced tests.
• The package documentation and framework documentation in signac-docs are up to date with these changes.
• I have updated the changelog and added any related issue and pull request numbers for future reference.

[joaander]

Here are fixes for the failing CI.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (a62f06d) 85.63% compared to head (26a8519) 85.65%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #957      +/-   ##
==========================================
+ Coverage   85.63%   85.65%   +0.01%     
==========================================
  Files          20       20              
  Lines        3461     3464       +3     
  Branches      758      759       +1     
==========================================
+ Hits         2964     2967       +3     
  Misses        338      338              
  Partials      159      159              

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[b-butler]

@joaander is there a way to get the CI to test both 'newest' and 'minimal' for Python 3.12 and Ubuntu?

[cbkerr]

I don't see any obvious problems in a short review.
I like the idea Josh proposed about the default key but don't have time to test it.

[joaander]

Thanks!