add ruby-2.1.3 to travis builds
remove ruby-2.0.0 - is anybody using this?
Merge branch 'master' of https://github.com/TelekomLabs/chef-ssh-hardening into ruby-2.13
Revert "remove ruby-2.0.0 - is anybody using this?"

This reverts commit f442ad91e7794a34ec98b7e8cfacd015173828db.
Merge pull request #47 from bkw/ruby-2.13

update travis builds to ruby 2.1.3