After seeing I can't upgrade to Date-Manip-5.52 because the sources don't exist on the mirrors anymore, I saw that version 5.54 is the latest. Please update, thank you...
and please rename ebuild from dev-perl/DateManip to dev-perl/Date-Manip for g-cpan detect better this module
5.54 is in the tree. I'd wait with renaming until the old version can be removed.