Returned default hardcoded ip

Author: antonyvorontsov

src/RabbitMQ.Client.Core.DependencyInjection/Configuration/RabbitMqClientOptions.cs

@@ -8,7 +8,7 @@ public class RabbitMqClientOptions
         /// <summary>
         /// RabbitMQ server.
         /// </summary>
-        public string HostName { get; set; }
+        public string HostName { get; set; } = "127.0.0.1";
 
         /// <summary>
         /// Port.