Bump pypa/cibuildwheel from 2.20.0 to 2.21.0 in the github-actions group

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


Updates `pypa/cibuildwheel` from 2.20.0 to 2.21.0
- [Release notes](https://github.com/pypa/cibuildwheel/releases)
- [Changelog](https://github.com/pypa/cibuildwheel/blob/main/docs/changelog.md)
- [Commits](pypa/cibuildwheel@v2.20.0...v2.21.0)

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

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/cibuildwheel.yml

@@ -56,7 +56,7 @@ jobs:
         echo "Setting CIBW_SKIP=$CIBW_SKIP"
 
     - name: "Building ${{ matrix.os }} (${{ matrix.arch }}) wheels"
-      uses: pypa/cibuildwheel@v2.20.0
+      uses: pypa/cibuildwheel@v2.21.0
       env:
         # Skips pypy py36,37
         CIBW_SKIP: ${{ env.CIBW_SKIP }}