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

Closes #37

Author: greenkeeper[bot]

package.json

@@ -29,7 +29,7 @@
     "babel-eslint": "^7.2.3",
     "babel-loader": "^7.1.2",
     "babel-preset-es2015": "^6.24.1",
-    "clean-webpack-plugin": "^1.0.0",
+    "clean-webpack-plugin": "^2.0.1",
     "css-loader": "^0.28.5",
     "extract-text-webpack-plugin": "^3.0.0",
     "node-sass": "^4.5.3",