[CrOS MultiDevice] Add vecore@ and jonmann@ as OWNERS

Change-Id: I89e063cc92572ce9590cfe6f6602f34489d9eebb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2537582
Auto-Submit: Kyle Horimoto <khorimoto@chromium.org>
Commit-Queue: James Vecore <vecore@google.com>
Reviewed-by: James Vecore <vecore@google.com>
Cr-Commit-Position: refs/heads/master@{#827338}

chromeos/components/multidevice/OWNERS

-khorimoto@chromium.org
 hansberry@chromium.org
+jonmann@chromium.org
+khorimoto@chromium.org
 nohle@chromium.org
+vecore@google.com
 # COMPONENT: OS>Systems>Multidevice