Bump python version in tests

Author: mlejva

.github/workflows/release_candidates.yml

@@ -56,7 +56,7 @@ jobs:
       - name: Set up Python
         uses: actions/setup-python@v4
         with:
-          python-version: "3.8"
+          python-version: "3.9"
 
       - name: Install and configure Poetry
         uses: snok/install-poetry@v1