Log Message:
textproc/ruby-haml: update to 5.0.4

## 5.0.4

Released on October 13, 2017
([diff](https://github.com/haml/haml/compare/v5.0.3...v5.0.4)).

* Fix `haml -c --stdin` regression in 5.0.2. \ 
[#958](https://github.com/haml/haml/pull/958) (thanks [Timo \ 
Göllner](https://github.com/TeaMoe))
* Ruby 2.5 support (it wasn't working due to Ripper API change). (Akira Matsuda)