chore(package): update nyc to version 9.0.1

https://greenkeeper.io/

Author: greenkeeperio-bot

package.json

@@ -30,7 +30,7 @@
     "chai": "^3.4.1",
     "coveralls": "^2.11.6",
     "mocha": "^3.0.0",
-    "nyc": "^8.1.0",
+    "nyc": "^9.0.1",
     "rimraf": "^2.5.0",
     "standard": "^8.0.0"
   }