[WORKFLOW] restrict docs deploy to default branch

Author: TheRedDaemon

.github/workflows/docs.yml

@@ -1,3 +1,6 @@
+# Only run for the default branch
+if: github.ref_name == github.event.repository.default_branch
+
 name: Deploy Sphinx documentation to Pages
 
 on:
@@ -17,4 +20,4 @@ jobs:
       id-token: write
     steps:
     - id: deployment
-      uses: sphinx-notes/pages@v3
+      uses: sphinx-notes/pages@v3