chore(package): update nyc to version 15.0.1

Closes #88

Author: greenkeeper[bot]

package.json

@@ -63,7 +63,7 @@
     "cz-conventional-changelog": "^2.1.0",
     "eslint": "^5.6.0",
     "jasmine": "^3.2.0",
-    "nyc": "^13.0.1",
+    "nyc": "^15.0.1",
     "protractor": "^5.4",
     "standard-version": "^4.2.0"
   },