chore(package): update nyc to version 12.0.1

Author: greenkeeper[bot]

package.json

@@ -80,7 +80,7 @@
     "request-promise": "^4.2.2",
     "istanbul": "^0.4.5",
     "mocha": "5.0.5",
-    "nyc": "^11.6.0",
+    "nyc": "^12.0.1",
     "webpack": "^4.2.0",
     "webpack-cli": "^2.0.13",
     "yargs": "^11.1.0"