Hello,

This patch removes all ruby versions which have reached EOL since they
no longer receive official security updates.

However, please do complain if you need to use one of these
versions. IMO, it is better to have a central place for them to receive
(unofficial) security updates (e.g. Debian will support ruby 2.1 until
2020), than to roll your own security updates (which is error-prone and
duplicate effort).