Cancel duplicate docbot workflows (#16368)

Author: maxsxu

.github/workflows/ci-cancel-duplicate-workflows.yaml

@@ -61,3 +61,9 @@ jobs:
           token: ${{ secrets.GITHUB_TOKEN }}
           cancelMode: allDuplicates
           workflowFileName: pulsar-ci.yaml
+      - name: cancel duplicate ci-documentbot.yml
+        uses: potiuk/cancel-workflow-runs@953e057dc81d3458935a18d1184c386b0f6b5738
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}
+          cancelMode: allDuplicates
+          workflowFileName: ci-documentbot.yml