Needs approval from an approver in each of these files:
- ~~[OWNERS](https://github.com/kubeflow/mpi-operator/blob/master/OWNERS)~~ [terrytangyuan]
Approvers can indicate their approval by writing `/approve` in a comment
Approvers can cancel approval by writing `/approve cancel` in a comment
I upgraded the controller-gen to fix an unknown field error.
xref: https://github.com/kubernetes-sigs/controller-tools/issues/402