Bump pypa/cibuildwheel from 2.20.0 to 2.21.0

Bumps [pypa/cibuildwheel](https://github.com/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
...

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

Author: dependabot[bot]

.github/workflows/publish_dartpy.yml

@@ -124,7 +124,7 @@ jobs:
 
       - name: Build wheels
         if: ${{ matrix.os != 'windows-latest' && (matrix.release_only == false || github.ref == 'refs/heads/main') }}
-        uses: pypa/cibuildwheel@v2.20.0
+        uses: pypa/cibuildwheel@v2.21.0
         env:
           # macOS
           MACOSX_DEPLOYMENT_TARGET: 14.0
@@ -134,7 +134,7 @@ jobs:
 
       - name: Build wheels (Windows)
         if: ${{ matrix.os == 'windows-latest' && (matrix.release_only == false || github.ref == 'refs/heads/main') }}
-        uses: pypa/cibuildwheel@v2.20.0
+        uses: pypa/cibuildwheel@v2.21.0
         env:
           # macOS
           MACOSX_DEPLOYMENT_TARGET: 14.0