chore(package): update nyc to version 14.1.0

Closes #20

Author: greenkeeper[bot]

package.json

@@ -48,7 +48,7 @@
     "chai": "^4.1.2",
     "coveralls": "^3.0.2",
     "mocha": "^5.2.0",
-    "nyc": "^13.0.1",
+    "nyc": "^14.1.0",
     "sinon": "^6.3.5",
     "sinon-chai": "^3.2.0",
     "ts-node": "^7.0.0",