publish docs only when pr is merged

Author: Massimiliano Pippi

.github/workflows/docs.yaml

@@ -1,9 +1,6 @@
 name: docs
 
 on:
-  push:
-    branches:
-      - master
   pull_request:
     paths:
       - 'docs/**'
@@ -57,7 +54,8 @@ jobs:
         run: mkdocs build -s
 
       - name: Deploy
-        if:
+        # publish docs only when PR is merged
+        if: github.event.pull_request.merged == 'true'
         uses: peaceiris/actions-gh-pages@v3
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}