chore(package): update nyc to version 15.0.1

Closes #2

Author: greenkeeper[bot]

package.json

@@ -72,7 +72,7 @@
 		"chai": "^4.1.2",
 		"coveralls": "^3.0.5",
 		"mocha": "^6.2.0",
-		"nyc": "^14.1.1",
+		"nyc": "^15.0.1",
 		"prettier": "^1.18.2",
 		"sonarjs": "^1.0.0",
 		"source-map-support": "^0.5.12",