Add maco to OWNERS.

Change-Id: I6e9d770a4a7c2a66774f9fe4fd342ceefade5e71
diff --git a/janitors/OWNERS b/janitors/OWNERS
index a28737e..c25d9e4 100644
--- a/janitors/OWNERS
+++ b/janitors/OWNERS
@@ -3,4 +3,5 @@
 cferris@google.com
 dwillemsen@google.com
 enh@google.com
+maco@google.com
 sadafebrahimi@google.com