chore(package): update nyc to version 15.1.0

Closes #3

Author: greenkeeper[bot]

package.json

@@ -33,7 +33,7 @@
     "faucet": "0.0.1",
     "glob": "^7.1.4",
     "jsdoc": "^3.6.2",
-    "nyc": "^14.1.1",
+    "nyc": "^15.1.0",
     "protocol-buffers": "^4.1.0",
     "zora": "^3.0.1"
   },