Bump nyc from 14.1.1 to 15.1.0 (#358)

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)

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

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

Author: dependabot-preview[bot]

package.json

@@ -102,7 +102,7 @@
     "husky": "^3.0.7",
     "mocha": "^6.2.2",
     "nodemon": "^2.0.1",
-    "nyc": "^14.1.1",
+    "nyc": "^15.1.0",
     "opn-cli": "^5.0.0",
     "sinon": "^7.5.0",
     "sinon-chai": "^3.0.0",