Move to python 3.12

[HGWright]

🚀 Pull Request

Description

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[HGWright]

@trexfeathers Two things about this:

1. Im a bit confused why this check is expected (could it be a handover of when that did run in this PR) but i still don't expect this.
2. Had to do force push for conflicts, I think because this used to have a file that did not exist locally (py39 lockfile).

[trexfeathers]

GitHub auto-merge must have 'required checks' in the branch protection rules. It looks like you (or maybe @bjlittle?) selected the following to be required (minus the CLA, which I selected):

This might mean we want to adjust our testing naming somehow so this doesn't become a problem every time we switch Python versions?