This release updates Ruby to version 2.2.8 to take advantage of multiple [security
fixes](https://www.ruby-lang.org/en/news/2017/09/14/ruby-2-2-8-released/). See the full [change
log](https://github.com/chef/chef-server/blob/master/CHANGELOG.md#121614-2017-09-21) for details on minor changes.