update python version

Author: fsbraun

.github/workflows/docs.yml

@@ -12,7 +12,7 @@ jobs:
       - name: Set up Python
         uses: actions/setup-python@v2
         with:
-          python-version: 3.9
+          python-version: 3.12
       - run: python -m pip install -r docs/requirements.txt
       - name: Build docs
         run: |