[+] add GHA workflow to publish devel docs (#599)

.github/workflows/build.yml

@@ -170,5 +170,12 @@ jobs:
     - name: Install dependencies
       run: pip install mike mkdocs-material mkdocs-glightbox
 
+    - name: Check if we should push to gh-pages
+      if: ${{ github.event_name == 'push' && github.ref == 'refs/heads/master' }}
+      run: |
+        echo ${{ github.event_name }}
+        echo ${{ github.ref }}
+        echo "push_opt=--push" >> $GITHUB_ENV 
+
     - name: Build mkdocs
-      run: mike --debug deploy devel
+      run: mike ${{ env.push_opt }} deploy devel