chore(package): update nyc to version 12.0.1

Author: greenkeeper[bot]

package.json

@@ -12,7 +12,7 @@
   "devDependencies": {
     "ava": "^0.25.0",
     "codecov": "^3.0.0",
-    "nyc": "^11.1.0",
+    "nyc": "^12.0.1",
     "semantic-release": "^15.0.0",
     "xo": "^0.21.0"
   },