chore(coverage): add nyc integration

Author: tusharmath

package.json

@@ -22,6 +22,7 @@
     "cz-conventional-changelog": "^1.2.0",
     "es-observable-tests": "^0.3.0",
     "ghooks": "^1.3.2",
+    "nyc": "^8.3.1",
     "semantic-release": "^4.3.5",
     "tslint": "^3.15.1",
     "tslint-microsoft-contrib": "^2.0.12",