Add a COMPONENT entry to the OWNERS file.

This is used to help people figure out where to file bugs against
code in the repo.

Change-Id: I0253359f703c67116785995b84ed5ff0bbcae28c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/1796610
Reviewed-by: Edward Lesmes <ehmaldonado@chromium.org>
Commit-Queue: Dirk Pranke <dpranke@chromium.org>

OWNERS

@@ -24,3 +24,5 @@ per-file chrome_set_ver=file://CROS_OWNERS
 per-file cros=file://CROS_OWNERS
 per-file cros_sdk=file://CROS_OWNERS
 per-file repo=file://CROS_OWNERS
+
+# COMPONENT: Infra>SDK