image-diff fix for javascript dependencies

Change-Id: I194c02d9695bafa1ed0c29d63e21cac959d65453
diff --git a/zuul.d/projects.yaml b/zuul.d/projects.yaml
index 7205947..9c7584c 100644
--- a/zuul.d/projects.yaml
+++ b/zuul.d/projects.yaml
@@ -174,6 +174,9 @@
 
 - project:
     name: plugins/image-diff
+    vars:
+      bazelisk_artifacts:
+        - "bazel-bin/plugins/{{ gerrit_plugin }}/{{ gerrit_plugin }}.js"
     templates:
       - non-core-plugin