test(mock-fs): update mock-fs version

failing on node 8 and up

Author: elpddev

package.json

@@ -45,7 +45,7 @@
     "karma-sinon": "^1.0.3",
     "load-grunt-tasks": "^3.2.0",
     "mocha": "^3.0.0",
-    "mock-fs": "^3.12.1",
+    "mock-fs": "^4.10.1",
     "shared-karma-files": "git://github.com/karma-runner/shared-karma-files.git#82ae8d02",
     "sinon": "^1.17.2"
   },