Update actions/checkout action to v3

Author: renovate[bot]

.github/workflows/lint.yml

@@ -9,7 +9,7 @@ jobs:
 
     steps:
       - name: Check out Git repository
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
 
       - name: Set up Python
         uses: actions/setup-python@v1