Make fromBeginning and fromTimestamp exclusive
Make fromBeginning and fromTimestamp exclusive

Cluster.fetchTopicOffsets accepts either fromBeginning OR fromTimestamp,
not both. While it technically would work to pass both in, it doesn't
make sense.

This change makes it so that you need to include one of them, but not both.

tulios/kafkajs,tulios/kafkajs,tulios/kafkajs,tulios/kafkajs