Add go mod vendor check to integration test (#1198)

Signed-off-by: Yi Chen <[email protected]>

.github/workflows/integration.yaml

@@ -35,6 +35,14 @@ jobs:
             exit 1
           fi
 
+      - name: Run go mod vendor
+        run: |
+          go mod vendor
+          if ! git diff --quiet; then
+            echo "Please run 'go mod vendor' to make vendored copy of dependencies"
+            exit 1
+          fi
+
       - name: Run go fmt check
         run: |
           make go-fmt