[security] fix issue WS-2018-0590

package.json

@@ -1,7 +1,7 @@
 {
   "dependencies": {
     "bootstrap": "^3.4.1",
-    "diff": "^2.2.3",
+    "diff": "^3.5.0",
     "flag-icon-css": "^0.8.6",
     "iframe-resizer": "^2.8.10",
     "jquery": ">=3.4.0"