Fix deprecated action

Author: brianhlin

.github/workflows/python-linters.yml

@@ -8,7 +8,7 @@ jobs:
     outputs:
       filelist: ${{ steps.python-files.outputs.filelist }}
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
     - id: python-files
       run: |
         echo "filelist=$(find . -type f -exec awk ' /^#!.*python/{print FILENAME} {nextfile}' {} + | tr '\n' ' ')" >> $GITHUB_OUTPUT