[owners] Specify component for //build

Change-Id: Ia770782025837a720b8a58d4777cbbc33ad6894a
Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/514103
Fuchsia-Auto-Submit: Shai Barack <shayba@google.com>
Commit-Queue: Auto-Submit <auto-submit@fuchsia-infra.iam.gserviceaccount.com>
Reviewed-by: David Turner <digit@google.com>
diff --git a/build/OWNERS b/build/OWNERS
index 636445a..1015c62 100644
--- a/build/OWNERS
+++ b/build/OWNERS
@@ -3,3 +3,5 @@
 jayzhuang@google.com
 fangism@google.com
 rudymathu@google.com
+
+# COMPONENT: Build>GN
\ No newline at end of file