devel/ruby-rgl: update to 0.5.4

2019-01 Release 0.5.4

Lia Skalkos
* Enable options to be passed to #write_to_graphic_file (4ca972). For details see PR #41
Horst Duchene
* Fix travis-ci errors
* Add new ruby versions
* Fix gemspec errors
* Fix lint warnings
* Use version stream 0.5.2

(taca)