Updated to Python 3.10 for checks

.github/workflows/tests.yml

@@ -43,10 +43,10 @@ jobs:
         tox-env: ["black", "lint", "docs"]
     steps:
       - uses: actions/checkout@v2
-      - name: Set up Python 3.9
+      - name: Set up Python 3.10
         uses: actions/setup-python@v2
         with:
-          python-version: 3.9
+          python-version: "3.10"
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip