[Compose] nslookup against google.com

docker-compose.yml

@@ -9,7 +9,7 @@ services:
         mysql-mailcow:
           condition: service_healthy
       healthcheck:
-        test: ["CMD", "nslookup", "mailcow.email", "127.0.0.1"]
+        test: ["CMD", "nslookup", "google.com", "127.0.0.1"]
         interval: 30s
         timeout: 3s
         retries: 10