Enable Prow for PR merging

[jlewi]

We should enable prow to review PRs .

It looks like the issue is that the ci-bots don't have permission on the repo

[chases2]

Hello!

It looks like Prow is trying to merge things, but there isn't an OWNERS file in this repository. As a result, the approve plugin can't determine who to assign for approval.

Information about OWNERS files and how to create them can be found at https://go.k8s.io/owners. A simple YAML file, such as the example below, can do for now.

See https://github.com/kubeflow/blog/pull/31 for an example of this; the link to OWNERS is currently dead.

# See the OWNERS docs at https://go.k8s.io/owners

approvers:
- some_github_name
- another_github_name