use Python 3.12 in documentation.yml of the generated package

Author: fdiblen

template/.github/workflows/{% if AddGitHubActionDocumentation %}documentation.yml{% endif %}

@@ -16,10 +16,10 @@ jobs:
       fail-fast: false
     steps:
       - uses: actions/checkout@v4
-      - name: Set up Python 3.9
+      - name: Set up Python 3.12
         uses: actions/setup-python@v5
         with:
-          python-version: 3.9
+          python-version: 3.12
       - name: Python info
         shell: bash -e {0}
         run: |
@@ -30,7 +30,7 @@ jobs:
           python -m pip install --upgrade pip setuptools
           python -m pip install .[dev,publishing]
       - name: Install pandoc using apt
-        run: sudo apt install pandoc        
+        run: sudo apt install pandoc
       - name: Build documentation
         run: make coverage doctest html
         working-directory: docs