Update exercises/etl/etl.rb
Update exercises/etl/etl.rb

Co-Authored-By: Pedro Gaspar <7954c463a08275d9bb6dd3c4436568c06f11ea12@gmail.com>
exercism/xruby,NeimadTL/ruby,NeimadTL/ruby,NeimadTL/ruby,exercism/xruby