devel/magit-popup: Mark DEPRECATED and set EXPIRATION_DATE
After devel/magit has been updated to 3.0.0, there is no consumer of
this port in the ports tree, so mark it DEPRECATED and set EXPIRATION_DATE.
PR: 256155
Submitted by: Yasuhiro Kimura <yasu@utahime.org> (maintainer)
Approved by: lwhsu (mentor)