chore(deps-dev): bump nyc from 14.1.1 to 15.1.0 (#41)

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[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

package.json

@@ -48,7 +48,7 @@
     "eslint-config-oclif-typescript": "^0.1",
     "jest-fixtures": "^0.6.0",
     "mocha": "^5",
-    "nyc": "^14",
+    "nyc": "^15",
     "semantic-release": "^17.0.7",
     "strip-indent": "^3.0.0",
     "typescript": "^3.7.5"