feat: use reference object description in amqp binding

amqp/README.md

@@ -30,8 +30,7 @@ Field Name | Type | Description
 ---|:---:|---
 <a name="channelBindingObjectIs"></a>`is` | string | Defines what type of channel is it. Can be either `queue` or `routingKey` (default).
 <a name="channelBindingObjectName"></a>`name` | string | When `is`=`routingKey`, this defines the actual routing pattern to route the message from the exchange to the queue.
-<a name="channelBindingObjectChannel"></a>`channel` | Map[string, any] | When `is`=`routingKey`, this defines the destination amqp queue.
-<a name="channelBindingObjectChannelRef"></a>`channel.$ref` | string | When `is`=`routingKey`, this defines an AsyncAPI channel `$ref` pointer to the destination amqp queue.
+<a name="channelBindingObjectChannel"></a>`channel` | [Reference Object](https://github.com/asyncapi/spec/blob/master/spec/asyncapi.md#referenceObject) | When `is`=`routingKey`, a $ref pointer to the definition of the channel where the amqp message is routed to. If defined, this property MUST point to a Channel Object in any location. Please note the channel property value MUST be a Reference Object and, therefore, MUST NOT contain a Channel Object.
 <a name="channelBindingObjectExchange"></a>`exchange` | Map[string, any] | When `is`=`routingKey`, this object defines the exchange properties.
 <a name="channelBindingObjectExchangeName"></a>`exchange.name` | string | The name of the exchange. It MUST NOT exceed 255 characters long.
 <a name="channelBindingObjectExchangeType"></a>`exchange.type` | string | The type of the exchange. Can be either `topic`, `direct`, `fanout`, `default` or `headers`.