Upgrade the kafka-clients library to 3.9.0

[mxcross]

reactor-kafka is still on kafka-clients 3.6.0. It would be beneficial to have this updated to the latest kafka-clients library which is currently 3.9.0.

Motivation

kafka-clients on lower versions than 3.8.0 are being detected by security scans as vulnerable due to improper enforcement of ACLs during migration of a cluster from ZooKeeper mode to KRaft mode.

Desired solution

Upgrade the kafka-clients library to at least 3.8.0, but 3.9.0 would be more desirable.

Considered alternatives

Additional context