update linter test with py37

.github/workflows/lint.yaml

@@ -11,10 +11,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
-      - name: Set up Python 3.6
+      - name: Set up Python 3.7
         uses: actions/setup-python@v2
         with:
-          python-version: 3.6
+          python-version: 3.7
       - name: Install pre-commit hook
         run: |
           pip install pre-commit