chore(deps): update dependency @types/node to v18 (#454)

Author: renovate-bot

packages/google-cloud-aiplatform/package.json

@@ -51,7 +51,7 @@
   },
   "devDependencies": {
     "@types/mocha": "^9.0.0",
-    "@types/node": "^16.0.0",
+    "@types/node": "^18.0.0",
     "@types/sinon": "^10.0.0",
     "c8": "^7.3.5",
     "gts": "^3.1.0",