Upstream support for Ruby 2.0 ended at the beginning of 2016, therefore we'd like to remove ruby20 soon. Your package depends on ruby:2.0, please use a recent ruby implementation and get this version stable, if the ruby:2.0 version had stable keywords. Note that these are old versions so you could also consider a cleanup.
I dropped all the old versions, and dropped ruby20 from the remaining ones. commit e5c183da286b54e8c6d6f7446821972be7a7831c Author: Jason Zaman <perfinion@g.o> Date: Thu Sep 1 23:59:35 2016 sys-libs/libselinux: Drop old Package-Manager: portage-2.2.28 commit 0efb71f31d1a29170364988d7e9f1b777b3ee258 Author: Jason Zaman <perfinion@g.o> Date: Fri Sep 2 00:38:45 2016 sys-libs/libselinux: Drop ruby20 bug 589422 Package-Manager: portage-2.2.28