chore(package): update uglifyjs-webpack-plugin to version 2.0.0

Author: greenkeeper[bot]

package.json

@@ -40,7 +40,7 @@
     "tslib": "1.9.3",
     "tslint": "5.11.0",
     "typescript": "^3.0.1",
-    "uglifyjs-webpack-plugin": "^1.2.7",
+    "uglifyjs-webpack-plugin": "^2.0.0",
     "webpack": "4.17.0",
     "webpack-cli": "3.1.0",
     "webpack-dev-server": "3.1.5"