fix doc

Author: antoinedemathelin

.github/workflows/check-docs.yml

@@ -10,10 +10,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
-    - name: Set up Python 3.11
+    - name: Set up Python 3.8
       uses: actions/setup-python@v2
       with:
-        python-version: '3.11'
+        python-version: '3.8'
     - name: Install doc dependencies
       run: |
         sudo apt install pandoc