fix workflow in private repo (#1728)

Author: xinsong-cui

.github/workflows/api-compat-verification.yml

@@ -14,6 +14,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
+        with:
+          token: ${{ secrets.CI_USER_PAT }}
+          fetch-depth: 0
       - name: Check for API compatibility
         if: ${{ !contains(github.event.pull_request.labels.*.name, 'acknowledge-api-break') }}
         run: |