chore(package): update rollup-plugin-uglify to version 4.0.0

Author: greenkeeper[bot]

package.json

@@ -64,7 +64,7 @@
     "rollup-plugin-commonjs": "^9.1.0",
     "rollup-plugin-json": "^3.0.0",
     "rollup-plugin-node-resolve": "^3.2.0",
-    "rollup-plugin-uglify": "^3.0.0",
+    "rollup-plugin-uglify": "^4.0.0",
     "rollup-watch": "^4.3.1"
   },
   "jest": {