Install Ruby with asdf instead of homebrew
What does this MR do?
Installs Ruby from ASDF instead of Homebrew.
Why was this MR needed?
The Homebrew version is broken.
What's the best way to test this MR?
Manually test the Ruby installation with the same steps as the Homebrew Formula: https://github.com/Homebrew/homebrew-core/blob/e38977e4002a9a0733b1139e53d582c73545b105/Formula/ruby.rb#L248-L261
What are the relevant issue numbers?
Fixes #126 (closed)