fix(package): update clean-webpack-plugin to version 2.0.1

Closes #238

Author: greenkeeper[bot]

package.json

@@ -42,7 +42,7 @@
     "babel-register": "^6.26.0",
     "bcryptjs": "^2.4.3",
     "body-parser": "^1.18.2",
-    "clean-webpack-plugin": "^0.1.19",
+    "clean-webpack-plugin": "^2.0.1",
     "copy-webpack-plugin": "^4.5.1",
     "css-loader": "^0.28.7",
     "express": "^4.16.1",