ci: try macos free-threading

Signed-off-by: Henry Schreiner <henryschreineriii@gmail.com>

Author: henryiii

.github/workflows/ci.yml

@@ -49,7 +49,7 @@ jobs:
     name: cibw on ${{ matrix.runs-on }}
     steps:
     - uses: actions/checkout@v4
-    - uses: pypa/cibuildwheel@v2.18
+    - uses: pypa/cibuildwheel@main
       with:
           package-dir: projects/hello-free-threading
       env: