ci: Update secret-scanner to use public action (#719)

* Update secret-scanner.yml

.github/workflows/secret-scanner.yml

@@ -10,21 +10,6 @@ jobs:
   scan_secret:
     name: Scan incoming changes
     runs-on: ubuntu-latest
-    container:
-      image: ghcr.io/aristanetworks/secret-scanner-service:main
-      options: --name sss-scanner
-    steps:
-      - name: Checkout ${{ github.ref }}
-        # Hitting https://github.com/actions/checkout/issues/334 so trying v1
-        uses: actions/checkout@v1
-        with:
-          fetch-depth: 0
+    steps: 
       - name: Run scanner
-        run: |
-          git config --global --add safe.directory $GITHUB_WORKSPACE
-          scanner commit . github ${{ github.repository }} \
-             --markdown-file job_summary.md \
-             ${{ github.event_name == 'pull_request' && format('--since-commit {0}', github.event.pull_request.base.sha) || ''}}
-      - name: Write result to summary
-        run: cat ./job_summary.md >> $GITHUB_STEP_SUMMARY
-        if: ${{ always() }}
+        uses: aristanetworks/secret-scanner-service-public@main