Update Python version in documentation workflow

Author: lukegre

.github/workflows/documentation.yml

@@ -23,7 +23,7 @@ jobs:
       - name: Set up Python
         uses: actions/setup-python@v5
         with:
-          python-version: '3.9'
+          python-version: '3.12'
           cache: pip
 
       - name: Install package with documentation dependencies