chore(package): update nyc to version 13.3.0

Closes #71

Author: greenkeeper[bot]

package.json

@@ -49,7 +49,7 @@
     "lint-staged": "^7.0.0",
     "npm-run-all": "^4.0.0",
     "npmpub": "^3.1.0",
-    "nyc": "^11.0.0",
+    "nyc": "^13.3.0",
     "pify": "^3.0.0",
     "prettier": "^1.5.2",
     "remark-cli": "^5.0.0",