Add admin.describeGroups

[Nevon]

Implements a new method on the Admin client, describeGroups. It works the same as the equivalent method on the Consumer, except it allows you to query by multiple groupIds.

Fixes #731

[JaapRood]

Looks good! The only thing I think we might be missing is providing the leader / partition assignor in the result. If I remember correctly the memberId of the consumer who was elected is what's used elsewhere as well, would that be appropriate?

[Nevon]

And before I forget, updating the TS type definitions.

EDIT: Done!

[Nevon]

The only thing I think we might be missing is providing the leader / partition assignor in the result. If I remember correctly the memberId of the consumer who was elected is what's used elsewhere as well, would that be appropriate?

We don't provide this in consumer.describeGroup, and I don't think we actually have a way to get it, since it's not part of the DescribeGroups response. The only place I can find with that information is in the JoinGroup response, which isn't relevant to the admin client.

[JaapRood]

Looks good to me!

[tzachshabtay]

Thanks for the quick turnaround! When can I expect to see a new package on npm? @Nevon @JaapRood

[Nevon]

There's a new beta release out already. I can't make any promises regarding when we'll make the next stable release.