devel/slf4j: Update 1.7.21 => 1.7.36
Commit log:
https://github.com/qos-ch/slf4j/compare/v_1.7.21...v_1.7.36
Replace PORTVERSION with DISTVERSION.
Apparently upstream stopped posting tarballs - change the source to maven.
PR: 287214
Approved by: skreuzer