chore(deps-dev): bump nyc from 11.9.0 to 15.1.0

Bumps [nyc](https://github.com/istanbuljs/nyc) from 11.9.0 to 15.1.0.
- [Release notes](https://github.com/istanbuljs/nyc/releases)
- [Changelog](https://github.com/istanbuljs/nyc/blob/master/CHANGELOG.md)
- [Commits](istanbuljs/nyc@v11.9.0...v15.1.0)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

package.json

@@ -27,7 +27,7 @@
     "coveralls": "^2.13.1",
     "eslint": "^3.19.0",
     "mocha": "^3.4.2",
-    "nyc": "^11.0.2",
+    "nyc": "^15.1.0",
     "pre-commit": "^1.2.2"
   },
   "nyc": {