Adding checkout to ensure git env execution

.github/workflows/notify-docs-triagers.yml

@@ -10,15 +10,18 @@ jobs:
   Notify-triagers:
     runs-on: ubuntu-latest
     steps:
+      - name: Checkout Repository
+        uses: actions/checkout@v2
+
       - name: Check PR Changes
         id: pr-changes
         run: |
-          md_files=$(git diff --name-only ${{ github.event.before }} ${{ github.sha }} | grep '\.md$' || true)
+          md_files=$(git diff --name-only ${{ github.event.before }} ${{ github.sha }} -- '*.md' || true)
           echo "::set-output name=md_changes::${md_files}"
 
       - name: Create Comment
         if: steps.pr-changes.outputs.md_changes != ''
         uses: mshick/[email protected]
         with:
           message: "This is a test comment to check workflow for changes to Markdown files."
-          repo-token: ${{ secrets.GH_TOKEN }}
+          repo-token: ${{ secrets.GH_TOKEN }}