Bump actions/cache from 5.0.5 to 6.0.0

Bumps [actions/cache](https://github.com/actions/cache) from 5.0.5 to 6.0.0.
- [Release notes](https://github.com/actions/cache/releases)
- [Changelog](https://github.com/actions/cache/blob/main/RELEASES.md)
- [Commits](actions/cache@27d5ce7...2c8a9bd)

---
updated-dependencies:
- dependency-name: actions/cache
  dependency-version: 6.0.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/buildifier.yaml

@@ -29,7 +29,7 @@ jobs:
 
       - name: Cache buildifier
         id: cache-buildifier
-        uses: actions/cache@27d5ce7f107fe9357f9df03efb73ab90386fccae  # v5.0.5
+        uses: actions/cache@2c8a9bd7457de244a408f35966fab2fb45fda9c8  # v6.0.0
         with:
           path: ./buildifier
           key: ${{ runner.os }}-buildifier-${{ env.BUILDIFIER_VERSION }}