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 +111,13 @@
     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 = if ENV['CI_SPEC_OPTIONS'].nil? || ENV['CI_SPEC_OPTIONS'].strip.empty?
+                           ['--format', 'progress']
+                         else
+                           ENV['CI_SPEC_OPTIONS'].strip.split + ['--format', 'progress']
+                         end
+    args.push('--').concat(additional_options).push('--')
     args.concat(Rake::FileList[pattern].to_a)
 
     ParallelTests::CLI.new.run(args)