fix(package): update fs-extra to version 4.0.2

Author: greenkeeper[bot]

package.json

@@ -51,7 +51,7 @@
     "postcss-polymer-loader"
   ],
   "dependencies": {
-    "fs-extra": "4.0.1",
+    "fs-extra": "4.0.2",
     "loader-utils": "1.1.0",
     "parse5": "3.0.2",
     "postcss": "6.0.11",