fix(package): update fs-extra to version 6.0.1

Closes #351

Author: greenkeeper[bot]

package.json

@@ -4,7 +4,7 @@
   "version": "1.1.0",
   "main": "bootstrap.js",
   "dependencies": {
-    "fs-extra": "~3.0.1",
+    "fs-extra": "~6.0.1",
     "grunt": "^1.0.1",
     "grunt-available-tasks": "~0.6.2",
     "grunt-composer": "~0.4.4",