Automatic merge from submit-queue

cluster/gce/coreos: add OWNERS

See #33965 for context.

The code in `cluster/gce/coreos` has mostly been written/maintained by @yifan-gu and myself thusfar, so I added our names to the owner list.

@ethernetdan has also volunteered as well (thanks!).

**Release note**:
```release-note
NONE
```

cc @roberthbailey