If you set up the symlinks to make ruby 2.6 the system
ruby, don't forget to remove the following files:

 rm ${PREFIX}/bin/ruby
 rm ${PREFIX}/bin/erb
 rm ${PREFIX}/bin/irb
 rm ${PREFIX}/bin/rdoc
 rm ${PREFIX}/bin/ri
 rm ${PREFIX}/bin/gem
 rm ${PREFIX}/bin/bundle
 rm ${PREFIX}/bin/bundler
 rm ${PREFIX}/bin/rake
