don't deploy if branch is not master

Author: flagarde

.github/workflows/docs.yml

@@ -76,6 +76,7 @@ jobs:
       url: ${{ steps.deployment.outputs.page_url }}
     runs-on: ubuntu-latest
     needs: docs
+    if: github.ref == 'refs/heads/master'
     steps:
       - name: Deploy to GitHub Pages
         id: deployment