chore(package): update nyc to version 12.0.2

Closes #9

Author: greenkeeper[bot]

package.json

@@ -37,7 +37,7 @@
     "eslint": "^4.4.1",
     "js-promisify": "^1.1.0",
     "mocha": "^4.0.0",
-    "nyc": "^11.1.0",
+    "nyc": "^12.0.2",
     "rimraf": "^2.6.1",
     "webpack": "^3.5.4",
     "yaml-loader": "^0.5.0"