Switch to Python 3.11 for CI tasks

.github/workflows/docs.yml

@@ -7,13 +7,13 @@ jobs:
     name: Build Docs
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           submodules: "recursive"
       - name: Set up Python
         uses: actions/setup-python@v4
         with:
-          python-version: 3.9
+          python-version: "3.11"
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip
@@ -78,7 +78,7 @@ jobs:
           fi
       - name: Checkout latest Docs
         continue-on-error: true
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           repository: ${{ env.DOCS_REPO }}
           path: ${{ env.DOCS_DIR }}