🤖 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/1b5252aec880aa76850f97b16980a6ce00c782c4/src/transforms/coverage:replace-nyc-by-c8.js
Please contact the author of the transform if you believe there was an error.

package.json

@@ -32,7 +32,7 @@
   ],
   "scripts": {
     "build": "rm -rf lib && babel src -d lib",
-    "cover": "nyc --reporter=lcov npm test",
+    "cover": "c8 --all --src src --reporter=lcov npm test",
     "esdoc": "esdoc",
     "lint-config": "fixpack --dryRun",
     "lint-config-and-fix": "fixpack || fixpack",
@@ -55,14 +55,14 @@
     "@total-order/lex": "^1.0.0",
     "@total-order/primitive": "^1.0.1",
     "ava": "3.15.0",
+    "c8": "7.7.3",
     "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"
+    "np": "7.4.0"
   },
   "ava": {
     "files": [