GitHub Actions: Python versions must not be quoted

[cclauss]

Pytest logs currently contain:

  File "/home/runner/work/bagit-python/bagit-python/bagit.py", line 1119, in get_hashers
    "Unable to continue: hashlib does not support any of the requested algorithms!"
ValueError: Unable to continue: hashlib does not support any of the requested algorithms!

[acdha]

The Python 3.7 part is making me wonder if we should switch to the official Python images instead.

[cclauss]

https://github.com/LibraryOfCongress/bagit-python/actions/runs/4471750912/jobs/7857032424

corresponds with

https://devguide.python.org/versions

Python 3.7 reaches end-of-life in ~3 months so you can choose to test/support it or drop support early.

Successfully set up CPython (3.7.16)
Successfully set up CPython (3.8.16)
Successfully set up CPython (3.9.16)
Successfully set up CPython (3.10.10)
Successfully set up CPython (3.11.2)

[acdha]

https://github.com/LibraryOfCongress/bagit-python/actions/runs/4471750912/jobs/7857032424

corresponds with

https://devguide.python.org/versions

Python 3.7 reaches end-of-life in ~3 months so you can choose to test/support it or drop support early.

Successfully set up CPython (3.7.16)
Successfully set up CPython (3.8.16)
Successfully set up CPython (3.9.16)
Successfully set up CPython (3.10.10)
Successfully set up CPython (3.11.2)

For most tools, we tend to track the support lifetime of common operating systems — for example, RHEL 7 and other distributions of that vintage have Python 3.7 as the default and that's fully supported for a year past when the core Python developers discontinue support.