Add explicit support for Python 3.12

[jack-mcivor]

Summary of changes

Add explicit support for Python 3.12

Pull Request Checklist

• Changes have tests
• Authors have been added to AUTHORS.md
• News fragment added in changelog.d. See CONTRIBUTING.md for details

[cclauss]

Please rebase so we can see if the tests now pass.

[goncalossilva]

Will this be going in anytime soon? Can I help to see it through? Our update to Python 3.12 is currently blocked on this. 🙏

[edgarrmondragon]

Will this be going in anytime soon? Can I help to see it through? Our update to Python 3.12 is currently blocked on this. 🙏

@goncalossilva This PR only adds metadata and dateutil is already compatible with Python 3.12, so this shouldn't block any downstream updates :)

[goncalossilva]

We turn all warnings into errors during testing, so we can't cope with:

../../../.cache/pypoetry/virtualenvs/ist-libs-RGqaVcAI-py3.12/lib/python3.12/site-packages/dateutil/tz/tz.py:37: in
EPOCH = datetime.datetime.utcfromtimestamp(0)
E DeprecationWarning: datetime.datetime.utcfromtimestamp() is deprecated and scheduled for removal in a future version. Use timezone-aware objects to represent datetimes in UTC: datetime.datetime.fromtimestamp(timestamp, datetime.UTC).

I realize that's our doing and also that I missed the 2.9.0 release just a few days ago which addresses this, so we can go ahead and update regardless of this particular ticket. Thanks! 🙏