chore(package): update nyc to version 12.0.2

Closes #27

Author: greenkeeper[bot]

package.json

@@ -37,7 +37,7 @@
     "loopback": "^3.6.0",
     "loopback-testing": "^1.4.0",
     "mocha": "^3.3.0",
-    "nyc": "^11.1.0",
+    "nyc": "^12.0.2",
     "semantic-release": "^7.0.2"
   },
   "config": {