[DRE-maint] ruby-joiner is marked for autoremoval from testing

[Debian testing autoremoval watch]

ruby-joiner 0.4.2-1 is marked for autoremoval from testing on 2020-03-23

It is affected by these RC bugs:
950963: ruby-joiner: FTBFS: Could not find gem 'sqlite3 (~> 1.3.8)' in any of the gem sources listed in your Gemfile