chore(package): update fs-extra to version 8.1.0

Closes #5

Author: greenkeeper[bot]

package.json

@@ -27,7 +27,7 @@
     "yeoman-generator": "^1.1.0"
   },
   "devDependencies": {
-    "fs-extra": "^2.0.0",
+    "fs-extra": "^8.1.0",
     "jshint": "^2.9.4",
     "mocha": "^4.0.0",
     "yeoman-assert": "^3.0.0",