Add support for Python 3.12

[hugovk]

The Python 3.12 release candidate is out! 🚀

Call to action

We strongly encourage maintainers of third-party Python projects to prepare their projects for 3.12 compatibilities during this phase, and where necessary publish Python 3.12 wheels on PyPI to be ready for the final release of 3.12.0.

See also https://dev.to/hugovk/help-test-python-312-beta-1508/

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The 3.8 and 3.9 failures are unrelated.

[codecov]

Codecov Report

Patch coverage: 100.00% and no project coverage change.

Comparison is base (b42e8b3) 83.33% compared to head (6f9bd9a) 83.33%.
Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #946   +/-   ##
=======================================
  Coverage   83.33%   83.33%           
=======================================
  Files          13       13           
  Lines        1374     1374           
  Branches      258      258           
=======================================
  Hits         1145     1145           
  Misses        152      152           
  Partials       77       77           

Files Changed	Coverage Δ
websocket/_core.py	81.42% <100.00%> (ø)

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[engn33r]

Thanks for the PR