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

[Debian testing autoremoval watch]

ruby-representable 3.0.4-1 is marked for autoremoval from testing on 2018-03-23

It (build-)depends on packages with these RC bugs:
888192: ruby-prof: FTBFS on ruby2.5: ArgumentError: incomplete format specifier; use %%
889159: ruby-prof: ruby-representable FTBFS with Ruby 2.5