build: use c8 for coverage (#236)

* build: use c8 for coverage

* chore: do our samples exercise more of the codebase

Co-authored-by: Benjamin E. Coe <bencoe@google.com>
Co-authored-by: Alexander Fenster <github@fenster.name>

packages/google-cloud-asset/package.json

@@ -29,13 +29,12 @@
     "Cloud Asset API"
   ],
   "scripts": {
-    "cover": "nyc --reporter=lcov mocha test/*.js && nyc report",
     "docs": "jsdoc -c .jsdoc.js",
     "lint": "eslint '**/*.js'",
-    "samples-test": "cd samples/ && npm link ../ && npm test && cd ../",
+    "samples-test": "c8 npm run samples-test-suite",
+    "samples-test-suite": "cd samples/ && npm link ../ && npm test && cd ../",
     "system-test": "mocha system-test/*.js smoke-test/*.js --timeout 600000",
-    "test-no-cover": "mocha test/*.js",
-    "test": "npm run cover",
+    "test": "c8 mocha",
     "fix": "eslint --fix '**/*.js'",
     "docs-test": "linkinator docs",
     "predocs-test": "npm run docs"
@@ -56,7 +55,7 @@
     "jsdoc-region-tag": "^1.0.2",
     "linkinator": "^1.5.0",
     "mocha": "^6.0.0",
-    "nyc": "^14.0.0",
+    "c8": "^7.0.0",
     "power-assert": "^1.6.0",
     "prettier": "^1.13.7"
   }