[CI] Add dependabot support and labeler workflow (#162)

Add dependabot support and labeler workflow

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Signed-off-by: Yuanhao Ji <jiyuanhao@apache.org>

.github/workflows/image.yml

@@ -80,7 +80,7 @@ jobs:
       uses: docker/setup-buildx-action@v2
 
     - name: Publish - Login to Quay Container Registry
-      if: ${{ github.event_name == 'push' }}
+      if: ${{ github.event_name == 'push' && github.repository_owner == 'vllm-project' }}
       uses: docker/login-action@v3
       with:
         registry: quay.io
@@ -94,7 +94,7 @@ jobs:
         cache-from: type=gha
         cache-to: type=gha,mode=max
         # only trigger when tag, branch/main push
-        push: ${{ github.event_name != 'pull_request' }}
+        push: ${{ github.event_name == 'push' && github.repository_owner == 'vllm-project' }}
         labels: ${{ steps.meta.outputs.labels }}
         tags: ${{ steps.meta.outputs.tags }}
         build-args: |