RubyGems versions for Ruby versions

rubygems_by_ruby.js

// From: https://github.com/ruby/setup-ruby/pull/551/files#diff-344d865bd0fa41eafba66242f01ff940b063438e51ec83de8e4a613910ee9637R38-R55
  if (engine === 'ruby') {
    const rubyFloatVersion = common.floatVersion(version)
    if (common.isHeadVersion(version)) {
      console.log('Ruby master builds use included RubyGems')
    } else if (rubyFloatVersion >= 3.0) {
      await exec.exec(gem, ['update', '--system'])
    } else if (rubyFloatVersion >= 2.6) {
      await exec.exec(gem, ['update', '--system', '3.4.22'])
    } else if (rubyFloatVersion >= 2.3) {
      await exec.exec(gem, ['update', '--system', '3.3.27'])
    } else {
      console.log(`Cannot update RubyGems for Ruby version ${version}`)
    }
  } else {
    // non MRI Rubies (TruffleRuby and JRuby)
    await exec.exec(gem, ['update', '--system'])
  }