🤖 chore: Use c8 instead of nyc.

These changes were automatically generated by a transform whose code can be found at:
  - https://github.com/make-github-pseudonymous-again/rejuvenate/blob/b30cf223897adb74ca4a854799d50b21d7e1959d/src/transforms/coverage:replace-nyc-by-c8.js
Please contact the author of the transform if you believe there was an error.

package.json

@@ -26,7 +26,7 @@
   ],
   "scripts": {
     "build": "babel --delete-dir-on-start --env-name production src -d lib",
-    "cover": "nyc --reporter=lcov npm test",
+    "cover": "c8 --all --src src --reporter=lcov npm test",
     "dev": "npm run lint -- --fix && npm run cover -- -- -st --fail-fast",
     "esdoc": "esdoc",
     "lint": "true",
@@ -49,14 +49,14 @@
     "babel-plugin-transform-remove-console": "6.9.4",
     "babel-plugin-unassert": "3.0.1",
     "babel-preset-power-assert": "3.0.0",
+    "c8": "7.12.0",
     "coveralls": "3.1.0",
     "esdoc": "1.1.0",
     "esdoc-inject-script-plugin": "1.0.0",
     "esdoc-inject-style-plugin": "1.0.0",
     "esdoc-standard-plugin": "1.0.0",
     "fixpack": "4.0.0",
     "np": "7.4.0",
-    "nyc": "15.1.0",
     "power-assert": "1.6.1",
     "regenerator-runtime": "0.13.7"
   },