fix(deps): update dependency google-auth-library to v2 (GoogleCloudPlatform#962)

Author: renovate[bot]

Diff for: endpoints/getting-started-grpc/package.json

@@ -17,7 +17,7 @@
     "test": "repo-tools test run --cmd ava -- -T 1m --verbose system-test/*.test.js"
   },
   "dependencies": {
-    "google-auth-library": "^1.3.1",
+    "google-auth-library": "^2.0.0",
     "grpc": "1.16.1",
     "jsonwebtoken": "^8.2.0",
     "yargs": "12.0.5"