Bump pypa/cibuildwheel from 2.19 to 2.21 in the actions group

Bumps the actions group with 1 update: [pypa/cibuildwheel](https://github.com/pypa/cibuildwheel).


Updates `pypa/cibuildwheel` from 2.19 to 2.21
- [Release notes](https://github.com/pypa/cibuildwheel/releases)
- [Changelog](https://github.com/pypa/cibuildwheel/blob/main/docs/changelog.md)
- [Commits](pypa/cibuildwheel@v2.19...v2.21)

---
updated-dependencies:
- dependency-name: pypa/cibuildwheel
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: actions
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/wheels.yml

@@ -44,7 +44,7 @@ jobs:
       with:
         submodules: true
 
-    - uses: pypa/cibuildwheel@v2.19
+    - uses: pypa/cibuildwheel@v2.21
 
     - name: Verify clean directory
       run: git diff --exit-code