Update build_docs.yml

Author: C-Achard

.github/workflows/build_docs.yml

@@ -4,6 +4,7 @@ on:
   push:
     branches:
       - main
+      - cy/docs-action
 
 jobs:
   build:
@@ -12,7 +13,7 @@ jobs:
 
     steps:
     - run: sudo apt-get update && sudo apt-get install libgl1
-    - run: /usr/local/bin/python -m pip install --upgrade pip
+    - run: pip install --upgrade pip
     - uses: actions/checkout@v1
     # Standard drop-in approach that should work for most people.
     - uses: ammaraskar/sphinx-action@master