chore(package): update nyc to version 13.2.0

Closes #54

Author: greenkeeper[bot]

package.json

@@ -30,7 +30,7 @@
     "eslint": "^4.11.0",
     "eslint-config-pedant": "^1.0.0",
     "mocha": "^5.0.0",
-    "nyc": "^11.3.0",
+    "nyc": "^13.2.0",
     "proxyquire": "^1.8.0",
     "sinon": "^4.1.2",
     "sinon-chai": "^2.14.0"