Fix the regular expression to match on `message.format.version`
Fix the regular expression to match on `message.format.version`

`[2,3]` would be a range allowing '2', '3' ... and ','.

This was introduced with 7c2f69ce, and this fix is mostly "cosmetical" as we wouldn't
ever see such a Kafka version in the wild (nor do we particularly care about it anywhere)

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