Pinning rabbitmq without a minor version broke when a default timeout was added to rabbitmq

[jdavidheiser]

I am submitting this mostly as a protip in case anybody is using this older example implementation - In rabbitmq/rabbitmq-server#2990, a default timeout was added to rabbitmq. When this timeout is hit by a job running for more than 15 minutes, Airflow workers will get into a bad state and stop accepting new work.

This affects this example because it pins only a major version, and not a minor version.

A short term fix is to pin rabbitmq to a specific minor version, such as 3.8.14, which does not have this default behavior. A better fix is to configure the timeout to something that makes sense for your own Airflow workflows.