Ruby 2.4.6 now available

Change effective on 01 April 2019

Ruby 2.4.6 includes the fixes from several CVEs from Rubygems with a bundled update of Rubygems: At Heroku, we already applied this patch to our version of Ruby 2.4.5 earlier. As a result, there is no functional difference when upgrading from 2.4.5 to 2.4.6.