pep639: setuptools license and license-files fields

[bjlittle]

🚀 Pull Request

Description

This pull-request complies with PEP639 for setuptools, also see license and license-files.

Additionally avoids the following setuptools deprecation warning:

!!
          ********************************************************************************
          Please consider removing the following classifiers in favor of a SPDX license expression:
          License :: OSI Approved :: BSD License
          See https://packaging.python.org/en/latest/guides/writing-pyproject-toml/#license for details.
          ********************************************************************************
!!

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.44%. Comparing base (275855f) to head (55d2c5e).
⚠️ Report is 45 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #377   +/-   ##
=======================================
  Coverage   97.44%   97.44%           
=======================================
  Files           7        7           
  Lines         625      625           
=======================================
  Hits          609      609           
  Misses         16       16           

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[scitools-ci]

• Please see: SciTools/.github#169

[stephenworsley]

Looks good.

N/A