gh-actions: protect the SSH deploy key

Author: mr-c

.github/workflows/deploy.yml

@@ -35,7 +35,7 @@ jobs:
         run:  ./website.sh --force-docker-pull --parallel
       - name: Pushes to another repository
         id: push_directory
-        uses: cpina/github-action-push-to-another-repository@main
+        uses: cpina/github-action-push-to-another-repository@55306faa4ed53b815ae49e564af8cfb359d32ae2
         env:
           SSH_DEPLOY_KEY: ${{ secrets.SSH_DEPLOY_KEY }}
         with: