[VOTE] KIP-1157: Enforce KafkaPrincipalSerde Implementation for KafkaPrincipalBuilder

[Johnny Wang]

Hi all,
I would like to call a vote for KIP-1157.
https://cwiki.apache.org/confluence/x/1gq9F

This KIP proposes to enforce the implementation of KafkaPrincipalSerde
alongside KafkaPrincipalBuilder, which is currently only noted in the
interface comments.

Thanks,
Wang