chore(package): update nyc to version 12.0.2

Closes #84

Author: greenkeeper[bot]

package.json

@@ -23,7 +23,7 @@
     "codecov": "^3.0.0",
     "lerna": "^2.1.2",
     "mocha": "^5.0.0",
-    "nyc": "^11.2.1",
+    "nyc": "^12.0.2",
     "sinon": "^5.0.0",
     "sinon-chai": "^3.0.0",
     "ts-node": "^5.0.0",