Add rbock as lacros owner.

This provides EMEA time-zone coverage for lacros/crosapi changes.

Change-Id: Ie987fb3aec72aeb30d43ba09631c1fd84b42b93d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2521870Reviewed-by: James Cook <jamescook@chromium.org>
Commit-Queue: Erik Chen <erikchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#824663}

chromeos/LACROS_OWNERS

@@ -2,3 +2,4 @@
 erikchen@chromium.org
 hidehiko@chromium.org
 jamescook@chromium.org
+rbock@google.com