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

[Debian testing autoremoval watch]

ruby-mail-room 0.10.0+really0.0.3-2 is marked for autoremoval from testing on 2020-05-02

It is affected by these RC bugs:
955678: ruby-mail-room: FTBFS: ERROR: Test "ruby2.7" failed: Failure/Error: expect(redis.client.instance_variable_get(:@connector)).to be_a Redis::Client::Connector::Sentinel