Sort your .rubocop.yml

hash-sort-by-key.rb

# http://dan.doezema.com/2012/04/recursively-sort-ruby-hash-by-key/

class Hash
  def sort_by_key(recursive = false, &block)
    self.keys.sort(&block).reduce({}) do |seed, key|
      seed[key] = self[key]
      if recursive && seed[key].is_a?(Hash)
        seed[key] = seed[key].sort_by_key(true, &block)
      end
      seed
    end
  end
end

sort-rubocop-yml.rb

require_relative './hash-sort-by-key'

File.write(
  '.rubocop.yml',
  YAML.load_file('.rubocop.yml').sort_by_key(true).to_yaml
)