fix(deps): update dependency google-auth-library to v4 (#601)

renovate[bot] · JustinBeckwith · commit baf9d397cd7a · 2019-05-10T22:04:32.000Z
diff --git a/package.json b/package.json
@@ -61,7 +61,7 @@
     "arrify": "^2.0.0",
     "async-each": "^1.0.1",
     "extend": "^3.0.1",
-    "google-auth-library": "^3.0.0",
+    "google-auth-library": "^4.0.0",
     "google-gax": "^0.26.0",
     "is-stream-ended": "^0.1.4",
     "lodash.merge": "^4.6.0",
