chore(deps-dev): bump nyc from 14.1.1 to 15.1.0

Bumps [nyc](https://github.com/istanbuljs/nyc) from 14.1.1 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@v14.1.1...v15.1.0)

---
updated-dependencies:
- dependency-name: nyc
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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

package.json

@@ -40,7 +40,7 @@
     "eslint-plugin-standard": "^4.0.1",
     "globby": "^10.0.1",
     "mocha": "^6.2.2",
-    "nyc": "^14.1.1",
+    "nyc": "^15.1.0",
     "recast": "^0.18.5",
     "semantic-release": "^17.4.5"
   },