OWNERS: Change maintainers to their user id's

Our prolog validation code has a bug where it can't handle a certain
amount of "." in email addresses. Switch over to the userid's of the
maintainers.

Change-Id: I7e390108814e87bb5fe9a44dcfc85964cce9561d
Signed-off-by: Andrew Geissler <geissonator@yahoo.com>
diff --git a/OWNERS b/OWNERS
index d814bbf..f28ddf0 100644
--- a/OWNERS
+++ b/OWNERS
@@ -32,8 +32,8 @@
 # data within them will be kept sorted.
 
 owners:
-- dung@os.amperecomputing.com
-- thang@os.amperecomputing.com
+- dcao-ampere
+- thangqn-ampere
 
 reviewers: