[Fix] python version in pythonapp.yml

.github/workflows/pythonapp.yml

@@ -12,7 +12,7 @@ jobs:
     - name: Set up Python 3.10
       uses: actions/setup-python@v1
       with:
-        python-version: 3.10
+        python-version: '3.10'
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip