Add 3.12 to CI, tox and metadata; use latest black and flake8

[Jmennius]

No description provided.

[luhn]

Probably better to fix the lint error rather than ignoring it. Maybe:

if not eventonly(predicate):
    return predicate

def derived_predicate(*arg):
     return predicate(arg[0])

return derived_predicate

[Jmennius]

Definitely, went for else clause.

[stevepiercy]

In addition to code and CI, would you please scan the documentation for Python support? I suspect searching for python 3 or 3.11 will turn up a few instances.

[stevepiercy]

Thank you! I approve the docs stuff only.

[Jmennius]

In addition to code and CI, would you please scan the documentation for Python support? I suspect searching for python 3 or 3.11 will turn up a few instances.

Done.
At this point, I would think that we may need a release notes/changes update as well? But I'm a bit confused about that because of difference in 2.0-branch and main.

Should we drop Python 3.7?

[Jmennius]

Thank you! I approve the docs stuff only.

Oh, sorry about the force-push, didn't expect you'd catch this so fast :)