Gives formatter deprecation warning when using zeus

[brandoncc]

When running specs via zeus the specs are run using the default progress formatter and the deprecation warning is shown, saying I need to use the legacy formatters gem. If I run my specs using rspec directly, I do not have this issue.

[vlad-shatskyi]

I have the same issue with spring.

[aeberlin]

Also seeing this issue via a rake task which invokes parallel_tests.

# lib/tasks/custom_parallel_tests_for_rspec.rake

require "parallel_tests"

namespace :rspec do
  desc 'Run custom parallel_tests with serialized output'
  task :parallel => :environment do
    default_options = [
      '-n', '8',
      '--serialize-stdout',
      '--combine-stderr',
      'spec/'
    ]

    ParallelTests::CLI.new.run(["--type", "rspec"] + default_options)
  end
end

The same warning can be observed by running bundle exec rake rspec:parallel with the above task.