fix(deps): update dependency @google-cloud/pubsub to v3 (#1972)

Author: renovate-bot

package.json

@@ -72,7 +72,7 @@
     "uuid": "^8.0.0"
   },
   "devDependencies": {
-    "@google-cloud/pubsub": "^2.0.0",
+    "@google-cloud/pubsub": "^3.0.0",
     "@grpc/grpc-js": "^1.0.3",
     "@grpc/proto-loader": "^0.6.0",
     "@types/async-retry": "^1.4.3",

samples/package.json

@@ -16,7 +16,7 @@
     "test": "mocha system-test/*.js --timeout 600000"
   },
   "dependencies": {
-    "@google-cloud/pubsub": "^2.0.0",
+    "@google-cloud/pubsub": "^3.0.0",
     "@google-cloud/storage": "^6.1.0",
     "node-fetch": "^2.6.7",
     "uuid": "^8.0.0",