Update the quickstart to grant access, otherwise users will see errors like

14:44:22,138 INFO [org.apache.kafka.clients.consumer.internals.AbstractCoordinator] (smallrye-kafka-consumer-thread-0) [Consumer clientId=kafka-consumer-from-kafka, groupId="microprofile-reactive-messaging-kafka-group-id"] (Re-)joining group
14:44:22,208 ERROR [org.apache.kafka.clients.consumer.internals.AbstractCoordinator] (smallrye-kafka-consumer-thread-0) [Consumer clientId=kafka-consumer-from-kafka, groupId="microprofile-reactive-messaging-kafka-group-id"] JoinGroup failed due to fatal error: Group authorization failed.
14:44:22,208 INFO [org.apache.kafka.clients.consumer.internals.AbstractCoordinator] (smallrye-kafka-consumer-thread-0) [Consumer clientId=kafka-consumer-from-kafka, groupId="microprofile-reactive-messaging-kafka-group-id"] Rebalance failed.: org.apache.kafka.common.errors.GroupAuthorizationException: Not authorized to access group: "microprofile-reactive-messaging-kafka-group-id"