upgrade github action version

Author: Fabien Coelho

.github/workflows/docs.yml

@@ -7,9 +7,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Set up Python
-        uses: actions/setup-python@v4
+        uses: actions/setup-python@v5
       - name: Install dependencies
         run: make venv.update
       - name: Check documentation syntax