Add mattm to OWNERS for netlog_viewer.
Add mattm to OWNERS for netlog_viewer.

Change-Id: Id8369a8bdd1ed5f3e080d22acfff237b6c30f04b
Reviewed-on: https://chromium-review.googlesource.com/c/1390706
Reviewed-by: Matt Menke <db2b536c538f3dbd8e890e06e08bcb9ec34adf6d@chromium.org>
Commit-Queue: Eric Roman <0ff3f513126b8ac069086ab3362de387f0f0f6a5@chromium.org>

catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult