ci: fix typo in python setup action

Author: machow

.github/workflows/ci.yml

@@ -94,7 +94,7 @@ jobs:
       - uses: actions/checkout@v2
       - uses: actions/setup-python@v2
         with:
-          python-version: 3.10
+          python-version: "3.10"
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip