Add Nicolas Cornu and Dimitri Merejkowsky as maintainers

Change-Id: I7b553d40d8f776acae8a72a783fdcfe3efaf5937
Reviewed-on: http://gerrit.aldebaran.lan:8080/16272
Tested-by: gerrit
Reviewed-by: ncornu <ncornu@aldebaran-robotics.com>