Adding rjkroege to gfx/overlay* OWNERS

Change-Id: Iad1bd0064c21c66c1471af62686033a8b3dcb845
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3872205


Commit-Queue: Robert Kroeger <rjkroege@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1042729}