Bump nyc from 14.1.1 to 15.0.0

Bumps [nyc](https://github.com/istanbuljs/nyc) from 14.1.1 to 15.0.0.
- [Release notes](https://github.com/istanbuljs/nyc/releases)
- [Changelog](https://github.com/istanbuljs/nyc/blob/master/CHANGELOG.md)
- [Commits](istanbuljs/nyc@v14.1.1...v15.0.0)

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

package.json

@@ -23,7 +23,7 @@
     "eslint-plugin-standard": "^3.0.1",
     "istanbul": "^0.4.5",
     "node-fetch": "^2.6.0",
-    "nyc": "^14.1.1",
+    "nyc": "^15.0.0",
     "teenytest": "^5.3.0",
     "testdouble": "^3.13.1"
   },