Add OWNERS for metrics.

It looks like all the other people who made significant contributions
to this project have left the team.

BUG=none
TEST=none

Change-Id: Ie572a43e85cee565c71c4101d1474e77e51449e5
Reviewed-on: https://chromium-review.googlesource.com/192008
Reviewed-by: Luigi Semenzato <semenzato@chromium.org>
Tested-by: Luigi Semenzato <semenzato@chromium.org>
Commit-Queue: Luigi Semenzato <semenzato@chromium.org>
diff --git a/metrics/OWNERS b/metrics/OWNERS
new file mode 100644
index 0000000..a680f7c
--- /dev/null
+++ b/metrics/OWNERS
@@ -0,0 +1,2 @@
+semenzato@chromium.org
+derat@chromium.org