Bump test suite to current versions

[JustAnotherArchivist]

CPython 3.7, PyPy 3.7, and PyPy 3.8 are EOL and unsupported.

The test on 3.12 currently fails. This is due to #613, and merging this PR should probably wait for #621 (or we should add a dependency on setuptools until that is resolved, as mentioned in https://github.com/jjjake/internetarchive/issues/613#issuecomment-1872954045).

[JustAnotherArchivist]

Yeah, it's the correct solution – if we don't migrate away from pkg_resources. But the plan (#621) is to do so, and once that is merged, nothing here will depend on setuptools anymore at runtime. Thus the test on Python 3.12 will also work fine at that point (without any changes in this PR).

[cclauss]

Yes. #621 is a better approach.

[JustAnotherArchivist]

Looks like this got obsoleted by e84edd1c although that did not remove the old PyPy versions. I'll create a new PR for that instead.