[Crash-utility] crash maintainers update

Hi, As of today, I'm stepping down as a crash co-maintainer because of a few reasons, mainly to get time to work on another project. Thank you everyone very much for helping me for about 4 years! with respect to makedumpfile, I will continue to maintain it until the handover is finished at least, so will be around the crash community for a while :-) Thanks, Kazu