CI update workflow

[gampnico]

• closes Refactor: Update CI workflow #258
  tests added / passed
  passes git diff upstream/master | flake8 --diff not applicable to yml files.
• whatsnew entry

[gampnico]

Some notes:

• I have set minimum ranges for pandas>=2.0 and numpy>=2.0. Pandas 3.0 is only supported for python 3.11+.
• bottleneck is listed as a dependency for the docs, but does not appear to be imported. Could this be removed?
• I have decided to keep the current CI requirements file as installing directly using pyproject would require separate optional dependency groups for a single package.

[fmaussion]

I have set minimum ranges for pandas>=2.0 and numpy>=2.0. Pandas 3.0 is only supported for python 3.11+.

OK, but this won't change anything in the tests since we don't enforce it there?

[gampnico]

I have set minimum ranges for pandas>=2.0 and numpy>=2.0. Pandas 3.0 is only supported for python 3.11+.

OK, but this won't change anything in the tests since we don't enforce it there?

Good catch, I missed that.

[gampnico]

Are we still maintaining support for Python 3.9 if it's no longer tested as part of the CI?