chore(deps): update dependency @google-cloud/nodejs-repo-tools to v3 (#328)

Author: renovate[bot]

handwritten/pubsub/samples/package.json

@@ -21,7 +21,7 @@
     "yargs": "^12.0.0"
   },
   "devDependencies": {
-    "@google-cloud/nodejs-repo-tools": "^2.0.11",
+    "@google-cloud/nodejs-repo-tools": "^3.0.0",
     "ava": "^0.25.0",
     "nyc": "^13.0.0",
     "proxyquire": "^2.0.0",