Replace deprecated classifier with licence expression (PEP 639)

[hugovk]

• https://peps.python.org/pep-0639/
• https://packaging.python.org/en/latest/specifications/core-metadata/
• https://discuss.python.org/t/pep-639-round-3-improving-license-clarity-with-better-package-metadata/53020/170

This depends on (at least) all these, thanks to everyone for making it happen:

• packaging 24.2 https://packaging.pypa.io/en/stable/changelog.html
• Hatchling 1.27 https://hatch.pypa.io/dev/history/hatchling/
• Twine 6.1.0 https://twine.readthedocs.io/en/stable/changelog.html
• PyPI publish GitHub Action v1.12.4 https://github.com/pypa/gh-action-pypi-publish/releases/tag/v1.12.4
• build-and-inspect-python-package v2.12.0 https://github.com/hynek/build-and-inspect-python-package/releases/tag/v2.12.0

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.48%. Comparing base (4762bdd) to head (6427174).
Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #236   +/-   ##
=======================================
  Coverage   99.48%   99.48%           
=======================================
  Files          11       11           
  Lines         782      782           
=======================================
  Hits          778      778           
  Misses          4        4           

Flag	Coverage Δ
macos-latest	97.69% <ø> (ø)
ubuntu-latest	97.69% <ø> (ø)
windows-latest	95.90% <ø> (ø)

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[glensc]

FYI: validate-pyproject update was also needed in my project:

  - repo: https://github.com/abravalheri/validate-pyproject
-    rev: v0.20.2
+    rev: v0.23

• https://github.com/Taxel/PlexTraktSync/pull/2191/files

[hugovk]

Thanks for the tip, that was already updated in #223.