Show latest target branch CI status in MR widget

It can be useful to contributors that merge to see the CI status of the target branch as well as the source branch.

Maybe we can show it next to the target branch in the MR widget?

Current

Screenshot_2019-06-05_at_15.13.09

Proposal

Screenshot_2019-06-05_at_15.14.13

Note this should be the latest pipeline that has completed, not just the latest pipeline. Seeing what is currently pending or running may not be the quickest indicator to the state of the target branch.