Druid 0.12.1-rc1 vote

[Jihoon Son]

Hi all,

We currently have no open issues/PRs for 0.12.1 (
https://github.com/druid-io/druid/milestone/26), so I created a branch for
0.12.1 (https://github.com/druid-io/druid/tree/0.12.1).

Let's vote on releasing RC1. Here is my +1.

Best,
Jihoon