Add fs-extra

package.json

@@ -45,7 +45,7 @@
         "@types/minimatch": "latest",
         "@types/minimist": "latest",
         "@types/mkdirp": "latest",
-        "@types/mocha": "latest",
+        "@types/mocha": "^5.2.2",
         "@types/node": "8.5.5",
         "@types/q": "latest",
         "@types/run-sequence": "latest",
@@ -59,6 +59,7 @@
         "chalk": "latest",
         "convert-source-map": "latest",
         "del": "latest",
+        "fs-extra": "^6.0.1",
         "gulp": "3.X",
         "gulp-clone": "latest",
         "gulp-concat": "latest",