Update cython requirement from <4,>=3.1 to >=3.2.4,<4

[dependabot]

Updates the requirements on cython to permit the latest version.

Changelog

Sourced from cython's changelog.

3.2.4 (2026-01-04)

Features added

• In preparation of Cython 3.3, a new decorator @collection_type(tname) can be used to advertise an extension type as being a 'sequence' or 'mapping'. This currently only has the effect of setting the Py_TPFLAGS_SEQUENCE flag on the type or not, but is provided for convenience to allow using the new decorator already in Cython 3.2 code.

• Several C++ exception declarations were added to libcpp.exceptions. (Github issue :issue:7389)

Bugs fixed

• Pseudo-literal default values of function arguments like arg=str() could generate invalid C code when internally converted into a real literal. (Github issue :issue:6192)

• The pickle serialisation of extension types using the auto_pickle feature was larger than necessary since 3.2.0 for types without Python object attributes. It is now back to the state before 3.2.0 again. (Github issue :issue:7443)

• Constants are now only made immortal on freethreading Python if they are not shared. (Github issue :issue:7439)

• PyDict_SetDefaultRef() is now used when available to avoid temporary borrowed references. (Github issue :issue:7347)

• Includes all fixes as of Cython 3.1.8.

3.2.3 (2025-12-14)

Features added

• The C-API declarations were updated to include the new PyList_*() functions. (Github issue :issue:7291)

• The Py_mod_gil module setting can now be changed with a C macro, overriding the freethreading_compatible directive setting. (Github issue :issue:7404)

Bugs fixed

... (truncated)

Commits

• 21bda42 Update changelog.
• ea5e926 Define missing C++ exception classes (#7389)
• c533d67 Add sequence return type annotations in Parsing.py (GH-7416)
• d056a18 Allow 'mapping' as @​collection_type() in preparation of 3.3, but without actu...
• d347c82 Remove exclusion of collection_type in test (#7442)
• fd6e825 Merge branch '3.1.x' into 3.2.x
• ce5c6cb Update changelog.
• 74b97f9 Fix arg=str() default argument (GH-6193)
• 9c9e5c7 Avoid immortalizing anything shared on freethreading (GH-7439)
• 9d5507b Fix accidental inefficiency in auto-pickling that always stored the object st...
• Additional commits viewable in compare view

[Kijewski]

@dependabot ignore this minor version

[dependabot]

OK, I won't notify you about version 3.2.x again, unless you re-open this PR.