chore(package): update clean-webpack-plugin to version 3.0.0

Closes #6

Author: greenkeeper[bot]

package.json

@@ -26,7 +26,7 @@
     "chessground": "^7.3.2"
   },
   "devDependencies": {
-    "clean-webpack-plugin": "^1.0.0",
+    "clean-webpack-plugin": "^3.0.0",
     "css-loader": "^2.0.0",
     "file-loader": "^3.0.0",
     "html-webpack-inline-source-plugin": "0.0.10",