Fix that 3.10 must be quoted

.github/workflows/lint.yml

@@ -19,7 +19,7 @@ jobs:
     - name: Set up Python
       uses: actions/setup-python@v1
       with:
-        python-version: 3.10
+        python-version: "3.10"
     - name: Install dependencies
       run:  pip install -U tox
     - name: Run Tox