Bump pypa/cibuildwheel from 2.20 to 2.21

Bumps [pypa/cibuildwheel](https://github.com/pypa/cibuildwheel) from 2.20 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@v2.20...v2.21)

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

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

.github/workflows/wheels.yml

@@ -36,7 +36,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - name: Build wheels
-        uses: pypa/cibuildwheel@v2.20
+        uses: pypa/cibuildwheel@v2.21
         env:
           CIBW_BUILD: ${{ matrix.python }}-${{ matrix.buildplat[1] }}_${{ matrix.buildplat[2] }}
           CIBW_ARCHS_MACOS: ${{ matrix.buildplat[2] }}