chore(package): update fs-extra to version 7.0.0

Closes #98

Author: greenkeeper[bot]

package.json

@@ -53,7 +53,7 @@
     "@types/node": "^9.4.6",
     "chai": "^4.1.2",
     "del": "^3.0.0",
-    "fs-extra": "^5.0.0",
+    "fs-extra": "^7.0.0",
     "glob": "^7.1.2",
     "gulp": "^4.0.0",
     "gulp-cli": "^2.0.1",