Pin python version to 3.10 for CI

Author: titusz

.github/workflows/tests.yaml

@@ -7,6 +7,8 @@ jobs:
     steps:
       - uses: actions/checkout@v2
       - uses: actions/setup-python@v2
+        with:
+          python-version: '3.10'
 
       - name: Install Poetry
         uses: abatilo/actions-poetry@v2.0.0