CI: Pin Cython to a specific commit Window PY3.13t builds (#61261)

Author: mroeschke

scripts/cibw_before_build.sh

@@ -7,6 +7,8 @@ done
 FREE_THREADED_BUILD="$(python -c"import sysconfig; print(bool(sysconfig.get_config_var('Py_GIL_DISABLED')))")"
 if [[ $FREE_THREADED_BUILD == "True"  ]]; then
     python -m pip install -U pip
-    python -m pip install -i https://pypi.anaconda.org/scientific-python-nightly-wheels/simple numpy cython
-    python -m pip install ninja meson-python versioneer[toml]
+    # python -m pip install -i https://pypi.anaconda.org/scientific-python-nightly-wheels/simple cython
+    # TODO: Remove below and uncomment above once https://github.com/cython/cython/pull/6717 no longer breaks tests
+    python -m pip install git+https://github.com/cython/cython.git@3276b588720a053c78488e5de788605950f4b136
+    python -m pip install ninja meson-python versioneer[toml] numpy
 fi