chore(package): update nyc to version 9.0.1

https://greenkeeper.io/

Author: greenkeeperio-bot

package.json

@@ -29,7 +29,7 @@
     "chai": "^3.5.0",
     "coveralls": "^2.11.12",
     "mocha": "^3.0.1",
-    "nyc": "^8.1.0",
+    "nyc": "^9.0.1",
     "standard": "^8.0.0",
     "standard-version": "^3.0.0"
   },