fix(package): update fs-extra to version 8.0.0

Closes #33

Author: greenkeeper[bot]

package.json

@@ -35,7 +35,7 @@
     "cross-spawn": "^5.1.0",
     "detect-port": "^1.2.1",
     "eslint-plugin-async-await": "0.0.0",
-    "fs-extra": "^4.0.0",
+    "fs-extra": "^8.0.0",
     "glob": "^7.0.5",
     "google-translate-api": "^2.3.0",
     "gulp-refresh": "^1.1.0",