Add OWNERS to tools/traffic_annotation/bin.

To update traffic annotation checker binaries one needs access to
chromium-tools-traffic_annotation bucket. To find access owners easier,
an OWNERS file is added to the folder.

Change-Id: I0f8dbdc6b599b0b5b159855a3e9d3e72cdb95e6f
Reviewed-on: https://chromium-review.googlesource.com/1168484
Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Reviewed-by: Georges Khalil <georgesak@chromium.org>
Commit-Queue: Ramin Halavati <rhalavati@chromium.org>
Cr-Commit-Position: refs/heads/master@{#582834}
2 files changed