[DOCS] Trigger the workflow after PR Labeler runs (#2823)

Co-authored-by: Jay Chia <[email protected]@users.noreply.github.com>

.github/workflows/build-docs.yml

@@ -10,6 +10,10 @@ on:
     branches: [main]
     types: [opened, synchronize, reopened, labeled]
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
+
 jobs:
   docgen:
     runs-on: ubuntu-latest