set sarama client KafkaVersion via config

[woodsaj]

see issue: #1053

from https://github.com/Shopify/sarama/blob/v1.19.0/config.go#L324-L330

The version of Kafka that Sarama will assume it is running against.
Defaults to the oldest supported stable version. Since Kafka provides
backwards-compatibility, setting it to a version older than you have
will not break anything, although it may prevent you from using the
latest features. Setting it to a version greater than you are actually
running may lead to random breakage.

[Dieterbe]

1. seems like sarama supports any delimiter between the digits, so rather than underscores, let's use dots so that the strings are actual version strings.
2. can we link or mention the supported ones? e.g. I notice there's a kafka release 1.1.1 for which there is no protocol version in sarama (even looking at latest master, which does support v2). this could be too much work to be worth it though.

[woodsaj]

seems like sarama supports any delimiter between the digits

this does appear to be true, but good catch. i just assumed that passing the supportVersion names would work, but ParseKafkaVersion actually wants the semver string. eg. 0.10.0.0

for version <1.0 it is using the regex ^0\.\d+\.\d+\.\d+$ and for >= 1.0 it is using ^\d+\.\d+\.\d+$

[woodsaj]

I notice there's a kafka release 1.1.1 for which there is no protocol version in sarama

Sarama only uses the version number to determine what Kafka features it can use. It does this with calls like

if bc.consumer.conf.Version.IsAtLeast(V0_10_0_0) {
		request.Version = 2
	}
	if bc.consumer.conf.Version.IsAtLeast(V0_10_1_0) {
		request.Version = 3
		request.MaxBytes = MaxResponseSize
	}
	if bc.consumer.conf.Version.IsAtLeast(V0_11_0_0) {
		request.Version = 4
		request.Isolation = ReadUncommitted // We don't support yet transactions.
	}

So the version provided doesn need to be in the list of supported versions.

[woodsaj]

@Dieterbe this should be good now