Upgrade uglify-js

Summary: Fixes https://github.com/facebook/flipper/issues/629

Reviewed By: mweststrate

Differential Revision: D18429396

fbshipit-source-id: 206211c0e6e248b0a05a59a1347cbd239e78c298

src/plugins/sections/d3/package.json

@@ -57,7 +57,7 @@
     "jsdom": "^15.1.1",
     "seedrandom": "^3.0.5",
     "smash": "0.0",
-    "uglify-js": "^3.6.5",
+    "uglify-js": "^3.6.8",
     "vows": "0.8"
   },
   "scripts": {