Add Python 3.13 to list of allowed Python versions (#11411)

## Summary

I believe we're already "Python 3.13-ready"? The main Ruff-impacting
change I see in https://docs.python.org/3.13/whatsnew/3.13.html is [PEP
696](https://peps.python.org/pep-0696/) which Jelle added in
https://github.com/astral-sh/ruff/pull/11120.

scripts/generate_known_standard_library.py

@@ -12,6 +12,7 @@ VERSIONS: list[tuple[int, int]] = [
     (3, 10),
     (3, 11),
     (3, 12),
+    (3, 13),
 ]
 
 with PATH.open("w") as f: