metric/perf: update OWNERS file.

Change-Id: Iddf32f7047287a98a06a7710efb8948b38a88eba
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1841654Reviewed-by: George Burgess <gbiv@chromium.org>
Reviewed-by: Gabriel Marin <gmx@chromium.org>
Commit-Queue: Gabriel Marin <gmx@chromium.org>
Cr-Commit-Position: refs/heads/master@{#728044}

chrome/browser/metrics/perf/OWNERS

 gmx@chromium.org
 # No Chromium committer status:
 # aalexand@google.com
-# lakshmana@chromium.org
+# dubin@google.com