Update python version used in test runs

.github/workflows/build-and-test.yml

@@ -19,10 +19,10 @@ jobs:
 
     steps:
     - uses: actions/checkout@v3
-    - name: Set up Python 3.8
+    - name: Set up Python 3.9
       uses: actions/setup-python@v3
       with:
-        python-version: "3.8"
+        python-version: "3.9"
     - name: Install python dependencies
       run: |
         python -m pip install --upgrade pip