(SERVER-2674) Update clj-parent to 4.2.8
(SERVER-2674) Update clj-parent to 4.2.8

This update downgrades JRuby to 9.2.8.0 to avoid a bug in 9.2.9.0.

puppetlabs/puppetserver,puppetlabs/puppet-server,puppetlabs/puppetserver,puppetlabs/puppet-server,puppetlabs/puppet-server,puppetlabs/puppetserver,puppetlabs/puppetserver