[SEC-7924] chore: pin third-party GitHub Actions to commit SHAs

Pin all third-party GitHub Actions to full-length commit SHAs to prevent
supply chain attacks. Addresses findings from the
third-party-action-not-pinned-to-commit-sha Semgrep rule.

Author: pkaeding

.github/workflows/release-please.yml

@@ -18,7 +18,7 @@ jobs:
       releases_created: ${{ steps.release.outputs.releases_created }}
 
     steps:
-      - uses: google-github-actions/release-please-action@v4
+      - uses: google-github-actions/release-please-action@e4dc86ba9405554aeba3c6bb2d169500e7d3b4ee # v4
         id: release
         with:
           token: ${{ secrets.GITHUB_TOKEN }}