quarkus: Quarkus 1.3.x: AMQP Emitter does not set content-type

Describe the bug When using an Emitter<JsonObject> of the quarkus-smallrye-reactive-messaging-amqp extension, Quarkus 1.2.1.Final added the Content-Type: application/json to the properties of the message. This is also documented under https://smallrye.io/smallrye-reactive-messaging/#_forwarding_messages_to_amqp: (Vert.x) JSON Array or JSON Object (send as binary with content type set to application/json)

In Quarkus 1.3.x, the content type property is not set in the message.

Expected behavior Content type should be set.

Actual behavior Content type is missing.

To Reproduce Steps to reproduce the behavior:

1. Download reproducer-smallrye-amqp-emitter-not-working.zip and unzip it.
2. In the unzipped directory run docker-compose up -d to start an activemq broker.
3. Run ./mvnw quarkusDev to start the container
4. Open http://localhost:8080/hello in a browser