ci(docs[tmp]): Trigger docs build on gp-sphinx-pytest branch

why: Preview doc-pytest-plugin adoption — need to verify rendered docs before merging.
what:
- Add gp-sphinx-pytest to on.push.branches in docs.yml

Author: tony

.github/workflows/docs.yml

@@ -4,6 +4,7 @@ on:
   push:
     branches:
       - master
+      - gp-sphinx-pytest
 
 permissions:
   contents: read