Loosen the Cython build dependency specifier to >= 3.2.0

PR #214

This patch changes the Cython build dependency specifier in `get_requires_for_build_wheel()` PEP 517 hook from `~= 3.2.0` (`>= 3.2.0, < 3.3.0`) to `>= 3.2.0`, removing the upper version bound.

The pinned version in `requirements/cython.txt` (`== 3.2.4`) is unchanged and continues to control the exact Cython version used in CI via `cibuildwheel`. This change only affects downstream packagers who disable build isolation or set their own constraints.

Author: gundalow

CHANGES/184.packaging.rst

@@ -1 +1,5 @@
-Update Cython to version 3.2.3 -- by :user:`jameshilliard`.
+Changed the Cython build dependency from ``~= 3.1.0`` to ``>= 3.2.0``,
+removing the upper version bound to avoid conflicts for downstream packagers
+-- by :user:`jameshilliard` and :user:`gundalow`.
+
+The upstream Cython version is pinned to 3.2.4 in the CI/CD environment.

CHANGES/188.packaging.rst

@@ -0,0 +1 @@
+184.packaging.rst

CHANGES/214.packaging.rst

@@ -0,0 +1 @@
+184.packaging.rst

packaging/pep517_backend/_backend.py

@@ -376,7 +376,7 @@ def get_requires_for_build_wheel(
     if is_pure_python_build:
         c_ext_build_deps = []
     else:
-        c_ext_build_deps = ['Cython ~= 3.2.0']
+        c_ext_build_deps = ['Cython >= 3.2.0']
 
     return _setuptools_get_requires_for_build_wheel(
         config_settings=config_settings,