Update to Sarama 1.20.0

[marqc]

Which problem is this PR solving?

Issue #1247

Short description of the changes

Upgrade shopify/Sarama dependency.
I tested ingester app against Kafka server 2.0.1 with log.message.format.version=2.0-IV1

[codecov]

Codecov Report

Merging #1248 into master will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff           @@
##           master   #1248   +/-   ##
======================================
  Coverage     100%    100%           
======================================
  Files         161     161           
  Lines        7206    7206           
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  Hits         7206    7206

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[vprithvi]

LGTM - Allow us some time to deploy a build of this internally before merging

[marqc]

@vprithvi how did your internal test go?

[vprithvi]

@marqc haven't yet tried it out because of code freeze. Hoping to have a response by next week.

[objectiser]

@marqc Could you rebase as the branch is now out of date?

@vprithvi Any more news on the internal tests? Would be good if we can get this in for 1.9.

[marqc]

@objectiser Changes merges with master without conflicts. This branch will always be out-of-date with master because there are multiple commits pushed to master everyday.

[objectiser]

@marqc sorry didn't look at the message properly, thought it was complaining about merge conflict :)

[yurishkuro]

Last I check Prithvi was about to deploy one instance with the upgraded sarama, I'll check with him tomorrow

[vprithvi]

We deployed and saw no significant changes in CPU/Memory/goroutines/etc. Nothing scientific, but good enough to merge! Apologies for the delays.