Geo::IP (aka dev-perl/Geo-IP) stopped receiving updates as of April 2018. We should move to GeoIP2::Reader::Database which supports the newer GeoIP2 databases. SpamAssassin supports it.
I'm not clear if there's a pre-existing ebuild for GeoIP2::Reader::Database.
See Also: https://wiki.apache.org/spamassassin/RelayCountryPlugin
See also: Gentoo bug #674852 mentions that dev-perl/GeoIP updates no longer work and everything should move to GeoIP2 capable libraries.