Add Python 3.13 and drop Python 3.8

[waylan]

trafficstars

Yesterday (2024-10-07), Python 3.13 was released and 3.8 reached end-of-life. This adjusts Python-Markdown's meta-data and tests to match.

However, I don't expect to immediately merge this. We can wait until we know we are working on our next major release. That is, unless there are some failing tests in 3.13.

[waylan]

Sigh. It appears that GitHub has not yet added the final release of Python 3.13. We'll need to rerun the tests when they do.

[facelessuser]

@waylan just allow prereleases

      with:
        python-version: ${{ matrix.python-version }}
        allow-prereleases: true

[cdce8p]

What's the current status here?

[waylan]

I forgot that this existed. Thanks for the reminder. It has been merged now.