setup.cfg -> pyproject.toml

[MetRonnie]

This email is notifying you of an upcoming deprecation that we have determined may affect you as a result of your recent upload to 'metomi-rose'.

In the future, PyPI will require all newly uploaded source distribution filenames to comply with PEP 625. Any source distributions already uploaded will remain in place as-is and do not need to be updated.

Specifically, your recent upload of 'metomi-rose-2.4.1.tar.gz' is incompatible with PEP 625 because it does not contain the normalized project name 'metomi_rose'.

In most cases, this can be resolved by upgrading the version of your build tooling to a later version that supports PEP 625 and produces compliant filenames. You do not need to remove the file.

If you have questions, you can email admin@pypi.org to communicate with the PyPI admin@pypi.org to communicate with the PyPI administrators.

[MetRonnie]

I thought we needed to specify the setuptools version in pyproject.toml[build-system] in order to fix the PEP 625 incompatibility, but it turns out it was just that we needed to use a newer Python version for the build (the minimum version of setuptools that is compatible with PEP 625 is not available on Python 3.9)

Seeing as I'd done the legwork (with the help of Copilot), I've kept the pyproject.toml conversion.

[wxtim]

Only semi relevent, but we should consider adding "workflows" and "workflow automation" to this list.

[MetRonnie]

(3.x test failure fixed by #2861)