Update MAINTAINERS
Update MAINTAINERS

Signed-off-by: Jonathan Rudenberg <3692bfa45759a67d83aedf0045f6cb635a966abf@titanous.com>

runcom/gotuf,theupdateframework/go-tuf,diogomonica/gotuf,dmcgowan/gotuf,cyli/gotuf,endophage/gotuf