Treat throttling errors as retriable

[richardartoul]

Describe the bug
kafkajs doesn't currently know about throttling errors and therefore treats them as unretriable, but they should be treated as retriable. These error codes are used by different kafka providers (my company included) to indicate that a client is doing too much of specific dimensions.

To Reproduce
N.A

Expected behavior
Client treats error as retriable.

Observed behavior
Client complains about a non-retriable error

(not showing full stack trace because it contains some identifiable information)

KafkaJSProtocolError: Unknown error code 89

 {
  retriable: false,
  helpUrl: undefined,
  type: 'KAFKAJS_UNKNOWN_ERROR_CODE',
  code: -99
}

Environment:

• KafkaJS version [v2.2.4]

Fix: #1695