fixing the reading the docker credentials from github action (#543)

Author: zylxjtu

.github/workflows/webhook-build.yaml

@@ -38,9 +38,14 @@ jobs:
 
       - name: Build and push webhook images to registry
         if: ${{ github.event_name != 'pull_request' }}
+        env:
+          DOCKER_USERNAME: ${{ secrets.DOCKER_USERNAME }}
+          DOCKER_SECRET: ${{ secrets.DOCKER_SECRET }}
         run: |
           echo "Building and pushing both webhook images to registry..."
-          echo "${{ secrets.DOCKER_SECRET }}" | docker login -u ${{ secrets.DOCKER_USERNAME }} --password-stdin
+          if [ -z "$DOCKER_USERNAME" ]; then echo "USERNAME is empty"; fi
+          if [ -z "$DOCKER_SECRET" ]; then echo "SECRET is empty"; fi
+          echo "$DOCKER_SECRET" | docker login -u "$DOCKER_USERNAME" --password-stdin
           cd helpers
           make docker-push-all
           echo "Both webhook images built and pushed successfully!"