chore(package): update nyc to version 12.0.1

Author: greenkeeper[bot]

package.json

@@ -14,7 +14,7 @@
     "ava": "^0.25.0",
     "codecov": "^3.0.0",
     "file-url": "^2.0.2",
-    "nyc": "^11.1.0",
+    "nyc": "^12.0.1",
     "semantic-release": "^15.0.0",
     "tempy": "^0.2.1",
     "xo": "^0.21.0"