fix(package): update vinyl-fs to version 3.0.0

Author: greenkeeper[bot]

package.json

@@ -31,7 +31,7 @@
     "lodash": "^4.17.4",
     "sass-graph": "^2.2.3",
     "through2": "^2.0.3",
-    "vinyl-fs": "^2.4.4"
+    "vinyl-fs": "^3.0.0"
   },
   "devDependencies": {
     "chai": "^4.0.1",