[pkg] Pin nyc to version 15.0.1

Author: lpinca

package.json

@@ -49,7 +49,7 @@
     "eslint-config-prettier": "^8.1.0",
     "eslint-plugin-prettier": "^4.0.0",
     "mocha": "^7.0.0",
-    "nyc": "^15.0.0",
+    "nyc": "15.0.1",
     "prettier": "^2.0.5",
     "utf-8-validate": "^5.0.2"
   }