Upgrade to Python3.11 and Cython3

[PeterMeisrimelModelon]

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[PeterMeisrimelModelon]

@jschueller
I've made sure this is compatible with Sundials 6.7 & 7, but seeing a lot of messages in the form of

[ERROR][rank 0][path/to/some/sundials/source/file.c:line][SUNGlobalFallbackErrHandler] The SUNDIALS SUNContext was corrupt or NULL when an error occurred. As such, error messages have been printed to stderr.

when running the tests with Sundials 7. This seems to only affect CVode tests that test invalid calls/errors (Likely also affects IDA/Kinsol, but CVode has better test coverage).

Have you seen this before?
(This is not critical; the tests still pass, just not super pretty)

[jschueller]

thats something I should have missed in the 6.x update because the SUNContext stuff was the new api of 6.x
anyway it should not block this long awaited new version