chore: pin googleapis/release-please-action action to 16a9c90 (#571)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/release-please.yml

@@ -11,7 +11,7 @@ jobs:
       pull-requests: write
       id-token: write
     steps:
-      - uses: googleapis/release-please-action@v4
+      - uses: googleapis/release-please-action@16a9c90856f42705d54a6fda1823352bdc62cf38 # v4
         id: release
       - uses: actions/checkout@v6
         if: ${{ steps.release.outputs.release_created }}