python support update --> 3.12

[pp-mo]

No description provided.

[echoix]

Python 3.13 is just 10 days away now

[ocefpaf]

BTW, conda-forge is shipping a py313 version of it and all the tests are passing. You can test it out with:

conda env create --name CFUNITS python=3.13 cf-units pytest -c conda-forge/label/python_rc
conda activate CFUNITS
pytest --pyargs cf_units

[trexfeathers]

We should now be in a good position to add this without missing a spot:

cf-units/cf_units/tests/test_coding_standards.py

Lines 121 to 122 in 539dbcc

	def test_python_versions():
	"""Confirm alignment of ALL files listing supported Python versions."""

[pp-mo]

Closed by #461