chore(package): update nyc to version 12.0.2 (#35)

Closes #34

Author: JustinBeckwith

packages/google-cloud-bigquery-datatransfer/package.json

@@ -62,7 +62,7 @@
     "intelli-espower-loader": "^1.0.1",
     "jsdoc": "^3.5.5",
     "mocha": "^5.2.0",
-    "nyc": "^11.0.0",
+    "nyc": "^12.0.2",
     "power-assert": "^1.5.0",
     "prettier": "^1.13.4",
     "through2": "^2.0.3"