fix(package): update webpack-manifest-plugin to version 2.0.3

Closes #84

Author: greenkeeper[bot]

package.json

@@ -108,7 +108,7 @@
     "url-loader": "0.6.2",
     "webpack": "3.8.1",
     "webpack-dev-server": "^2.11.1",
-    "webpack-manifest-plugin": "2.0.0-rc.2",
+    "webpack-manifest-plugin": "2.0.3",
     "whatwg-fetch": "2.0.3"
   },
   "devDependencies": {