rules_cros: add folks to OWNERS

We've all done (and plan to continue doing) meaningful work on this
project. Having us all in this list seems like a good idea.

BUG=None
TEST=None

Change-Id: I05db33e9417adad3ddf1e3b85b0fb12ec1bfe1ca
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/rules_cros/+/3661671
Reviewed-by: Sloan Johnson <sloanjohnson@google.com>
Tested-by: George Burgess <gbiv@chromium.org>
Commit-Queue: George Burgess <gbiv@chromium.org>
Reviewed-by: Greg Edelston <gredelston@google.com>
Owners-Override: Greg Edelston <gredelston@google.com>
diff --git a/OWNERS b/OWNERS
index cd91e85..32391e6 100644
--- a/OWNERS
+++ b/OWNERS
@@ -1 +1,4 @@
 cjmcdonald@chromium.org
+gbiv@chromium.org
+mbenfield@google.com
+sloanjohnson@google.com