Use c8 for code coverage

Author: novemberborn

.gitignore

@@ -1,4 +1,3 @@
 node_modules
 yarn.lock
-.nyc_output
 coverage

package.json

@@ -8,7 +8,7 @@
 		"node": ">=10.18.0 <11 || >=12.14.0 <13 || >=14"
 	},
 	"scripts": {
-		"test": "xo && nyc ava",
+		"test": "xo && c8 ava",
 		"integration": "node ./test/integration/test.js"
 	},
 	"files": [
@@ -42,6 +42,7 @@
 	"devDependencies": {
 		"ava": "^2.3.0",
 		"babel-eslint": "^10.0.2",
+		"c8": "^7.2.0",
 		"chalk": "^4.1.0",
 		"del": "^5.0.0",
 		"eslint": "6.2.0",
@@ -50,7 +51,6 @@
 		"execa": "^4.0.2",
 		"js-combinatorics": "^0.5.4",
 		"listr": "^0.14.3",
-		"nyc": "^15.1.0",
 		"outdent": "^0.7.0",
 		"pify": "^5.0.0",
 		"tempy": "^0.5.0",
@@ -84,7 +84,7 @@
 			"ava/no-ignored-test-files": "off"
 		}
 	},
-	"nyc": {
+	"c8": {
 		"reporter": [
 			"html",
 			"lcov",