chore(package): update uglifyjs-webpack-plugin to version 2.2.0

Closes #62

Author: greenkeeper[bot]

package.json

@@ -42,7 +42,7 @@
     "cp-cli": "~1.1.2",
     "webpack": "~3.12.0",
     "awesome-typescript-loader": "~3.5.0",
-    "uglifyjs-webpack-plugin": "~1.2.5",
+    "uglifyjs-webpack-plugin": "~2.2.0",
     "copy-webpack-plugin": "~4.5.1",
     "jest": "~22.4.3",
     "jest-junit-reporter": "~1.1.0",