Change to Python 3.9

Author: jasongrout

.github/workflows/deploy.yml

@@ -17,7 +17,7 @@ jobs:
       - name: Setup Python
         uses: actions/setup-python@v2
         with:
-          python-version: '3.10'
+          python-version: '3.9'
       - name: Install the dependencies
         run: |
           python -m pip install -r requirements.txt