deps: Update dependency @googleapis/sqladmin to v19 (#369)

Author: renovate-bot

package-lock.json

@@ -85,7 +85,7 @@
     "url": "git+https://github.com/GoogleCloudPlatform/cloud-sql-nodejs-connector"
   },
   "dependencies": {
-    "@googleapis/sqladmin": "^18.0.0",
+    "@googleapis/sqladmin": "^19.0.0",
     "gaxios": "^6.1.1",
     "google-auth-library": "^9.2.0",
     "p-throttle": "^5.1.0"