add keithlee to chromeos/services/ime/OWNERS

Change-Id: I47ddf6f917faff92a1b639c1f09cab3191d79f56
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1833028Reviewed-by: Shu Chen <shuchen@chromium.org>
Reviewed-by: Keith Lee <keithlee@chromium.org>
Commit-Queue: Keith Lee <keithlee@chromium.org>
Auto-Submit: Keith Lee <keithlee@chromium.org>
Cr-Commit-Position: refs/heads/master@{#707727}

chromeos/services/ime/OWNERS

 googleo@chromium.org
+keithlee@chromium.org
 shuchen@chromium.org
 
 per-file ime_sandbox_hook.*=file://sandbox/linux/OWNERS