chore(deps): update dependency c8 to v7 (#493)

Author: renovate-bot

packages/google-cloud-node/package.json

@@ -53,7 +53,7 @@
     "@types/mocha": "^5.2.7",
     "@types/node": "^12.0.0",
     "@types/sinon": "^7.5.1",
-    "c8": "^6.0.0",
+    "c8": "^7.0.0",
     "codecov": "^3.0.2",
     "eslint": "^6.0.0",
     "eslint-config-prettier": "^6.0.0",

packages/google-cloud-node/samples/package.json

@@ -19,7 +19,7 @@
     "yargs": "^15.0.0"
   },
   "devDependencies": {
-    "c8": "^6.0.0",
+    "c8": "^7.0.0",
     "chai": "^4.2.0",
     "mocha": "^6.0.0",
     "uuid": "^3.3.0"