Add siyamed@ to top level OWNERS.

Test: We've tested him long enough.
Change-Id: I96dfe21c6b44c80034108833dd3e905408ac76a2
diff --git a/OWNERS b/OWNERS
index 091f1e7..79dba6e 100644
--- a/OWNERS
+++ b/OWNERS
@@ -15,6 +15,7 @@
 [email protected]
 [email protected]
 [email protected]
[email protected]
 [email protected]
 [email protected]
 [email protected]