add clean-webpack-plugin as dev dependency

Author: tiagoschenkel

package.json

@@ -74,6 +74,7 @@
     "bluebird": "^3.5.3",
     "browserify-versionify": "^1.0.6",
     "chai": "^4.2.0",
+    "clean-webpack-plugin": "^1.0.0",
     "copy-webpack-plugin": "^4.6.0",
     "easeljs": "^1.0.2",
     "es6-map": "^0.1.5",

yarn.lock

@@ -1070,6 +1070,13 @@ [email protected]:
   dependencies:
     source-map "~0.6.0"
 
+clean-webpack-plugin@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.npmjs.org/clean-webpack-plugin/-/clean-webpack-plugin-1.0.0.tgz#f184b9c26d12983d639828e0548ae2080e84b6a7"
+  integrity sha512-+f96f52UIET4tOFBbCqezx7KH+w7lz/p4fA1FEjf0hC6ugxqwZedBtENzekN2FnmoTF/bn1LrlkvebOsDZuXKw==
+  dependencies:
+    rimraf "^2.6.1"
+
 cli-cursor@^1.0.2:
   version "1.0.2"
   resolved "https://registry.npmjs.org/cli-cursor/-/cli-cursor-1.0.2.tgz#64da3f7d56a54412e59794bd62dc35295e8f2987"