parallel_spec_standalone: use --format progress

For the past decade, people used a .rspec_parallel to configure this. We
can set it directly in the rake task. That enables us to remove the
.rspec_parallel and ultimately reduces the number of files required for
pdk update/modulesync.

lib/puppetlabs_spec_helper/rake_tasks.rb

@@ -111,8 +111,9 @@
  warn 'No files for parallel_spec to run against'
  else
 
- args = ['-t', 'rspec']
- args.push('--').concat(ENV['CI_SPEC_OPTIONS'].strip.split).push('--') unless ENV['CI_SPEC_OPTIONS'].nil? || ENV['CI_SPEC_OPTIONS'].strip.empty?
+ args = ['--type', 'rspec']
+ additional_options = ['--format', 'progress'] + ENV['CI_SPEC_OPTIONS'].to_s.strip.split
+ args.push('--').concat(additional_options).push('--')
  args.concat(Rake::FileList[pattern].to_a)
 
  ParallelTests::CLI.new.run(args)