fix(ci): prevent PRs from pushing to release branch

Author: dachrisch

.github/workflows/booklet.yml

@@ -47,6 +47,7 @@ jobs:
           path: ${{ env.OUT_PATH }}
 
       - name: 🎉 Push to stable branch
+        if: github.event_name == 'push'
         uses: s0/git-publish-subdir-action@develop
         env:
           REPO: self