chore: adjust python version (#122)

.github/workflows/python-tests.yml

@@ -17,10 +17,10 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-      - name: Set up Python 3.8
+      - name: Set up Python 3.9
         uses: actions/setup-python@v5
         with:
-          python-version: 3.8
+          python-version: 3.9
       - name: Install dependencies
         run: |
           pip install poetry