[PubSub RabbitMQ] RoutingKey information doesn't work

[olitomlinson]

Docs were never produced for this issue https://github.com/dapr/components-contrib/pull/2962

Describe the issue

https://docs.dapr.io/reference/components-reference/supported-pubsub/setup-rabbitmq/#use-topic-exchange-to-route-messages

The information fails to mention that a subscription must also set the queueName on each subscription.

Without setting the queueName, only one queue will be created, and all routing keys will route to that queue, which means all subscribers will bind to that queue, which will not give the desired results.

The subscription yaml example also needs changing to :

apiVersion: dapr.io/v2alpha1
kind: Subscription
metadata:
  name: orderspubsub
spec:
  topic: B
  routes: 
    default: /B
  pubsubname: pubsub
  metadata:
    routingKey: keyA
    queueName: queue-A