build(deps): bump actions/cache from 4 to 6 (#9513)

Bumps [actions/cache](https://github.com/actions/cache) from 4 to 6.
- [Release notes](https://github.com/actions/cache/releases)
- [Changelog](https://github.com/actions/cache/blob/main/RELEASES.md)
- [Commits](https://github.com/actions/cache/compare/v4...v6)

---
updated-dependencies:
- dependency-name: actions/cache
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/server-test.yml

@@ -27,7 +27,7 @@ jobs:
         run: echo "version=2.6.2" >> "$GITHUB_OUTPUT"
       - name: Cache bazel-remote
         id: cache-bazel-remote
-        uses: actions/cache@v4
+        uses: actions/cache@v6
         with:
           path: $RUNNER_TOOL_CACHE/local/bazel-remote
           key: bazel-remote-v${{ steps.bazel-remote-version.outputs.version }}-${{ runner.os }}-${{ runner.arch }}