chore(package): update rollup-plugin-uglify to version 6.0.1

Closes #6

Author: greenkeeper[bot]

package.json

@@ -107,7 +107,7 @@
     "rollup-plugin-node-resolve": "^3.0.0",
     "rollup-plugin-sourcemaps": "^0.4.2",
     "rollup-plugin-typescript2": "^0.15.1",
-    "rollup-plugin-uglify": "^4.0.0",
+    "rollup-plugin-uglify": "^6.0.1",
     "semantic-release": "^15.6.0",
     "ts-jest": "^23.0.0",
     "ts-node": "^7.0.0",