feature py3.12 support

[Adoni5]

Add Py3.12 support. Things to watch out for:

• External package support - particularly mappy-rs and ReadfishSummarise. These should have Py3.12 wheels but mappy-rs in particular needs a bit of inspection, I know for a fact the py3.12 wheel was trying to get rid of some memory shenanigans around the index and no-one knows if that was working when the Py3.12 wheel was rushed out. Also check ONT packages for py3.12
• Adding py3.12 to the CI tests

[Adoni5]

Seems legit

[mattloose]

Perhaps delete?

[Adoni5]

then my comment would make no sense, i've reported it and hidden it as spam