Fix Ruby 2.7 warning for #add_terminal_auth call

What does this MR do?

In Ruby 3.0, positional arguments and keyword arguments will be separated. Ruby 2.7 will warn for behaviors that will change in Ruby 3.0. In most cases, you can avoid the incompatibility by adding the double splat operator. It explicitly specifies passing keyword arguments instead of a Hash object.

Part of #257438 (closed)

With Ruby 2.7.1

$ ss spec/models/clusters/platforms/kubernetes_spec.rb:375
[TEST PROF INFO] Spring detected
/Users/tkuah/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/acts-as-taggable-on-6.5.0/lib/acts_as_taggable_on/tagging.rb:9: warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call
/Users/tkuah/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/activerecord-6.0.3.1/lib/active_record/associations.rb:1657: warning: The called method `belongs_to' is defined here
/Users/tkuah/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/marginalia-1.9.0/lib/marginalia.rb:94: warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call
/Users/tkuah/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/activerecord-6.0.3.1/lib/active_record/connection_adapters/postgresql_adapter.rb:648: warning: The called method `execute_and_clear_without_marginalia' is defined here
/Users/tkuah/code/ee-gdk/gitlab/lib/backup/files.rb:10: warning: already initialized constant Backup::Files::DEFAULT_EXCLUDE
/Users/tkuah/code/ee-gdk/gitlab/lib/backup/files.rb:10: warning: previous definition of DEFAULT_EXCLUDE was here
Running via Spring preloader in process 8551
/Users/tkuah/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/acts-as-taggable-on-6.5.0/lib/acts_as_taggable_on/tagging.rb:9: warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call
/Users/tkuah/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/activerecord-6.0.3.1/lib/active_record/associations.rb:1657: warning: The called method `belongs_to' is defined here
/Users/tkuah/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/marginalia-1.9.0/lib/marginalia.rb:94: warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call
/Users/tkuah/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/activerecord-6.0.3.1/lib/active_record/connection_adapters/postgresql_adapter.rb:648: warning: The called method `execute_and_clear_without_marginalia' is defined here
Run options: include {:focus=>true, :locations=>{"./spec/models/clusters/platforms/kubernetes_spec.rb"=>[375]}}

==> Setting up Gitaly...
/Users/tkuah/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/acts-as-taggable-on-6.5.0/lib/acts_as_taggable_on/tagging.rb:9: warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call
/Users/tkuah/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/activerecord-6.0.3.1/lib/active_record/associations.rb:1657: warning: The called method `belongs_to' is defined here
/Users/tkuah/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/marginalia-1.9.0/lib/marginalia.rb:94: warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call
/Users/tkuah/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/activerecord-6.0.3.1/lib/active_record/connection_adapters/postgresql_adapter.rb:648: warning: The called method `execute_and_clear_without_marginalia' is defined here
    Gitaly set up in 162.819864 seconds...
/Users/tkuah/code/ee-gdk/gitlab/config/initializers/forbid_sidekiq_in_transactions.rb:50: warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call
/Users/tkuah/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/activerecord-6.0.3.1/lib/active_record/transactions.rb:334: warning: The called method `committed!' is defined here
/Users/tkuah/code/ee-gdk/gitlab/app/validators/addressable_url_validator.rb:83: warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call
/Users/tkuah/code/ee-gdk/gitlab/lib/gitlab/url_blocker.rb:22: warning: The called method `validate!' is defined here
/Users/tkuah/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/state_machines-activerecord-0.6.0/lib/state_machines/integrations/active_record.rb:511: warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call
/Users/tkuah/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/activerecord-6.0.3.1/lib/active_record/suppressor.rb:43: warning: The called method `save' is defined here
/Users/tkuah/code/ee-gdk/gitlab/spec/support/helpers/stubbed_feature.rb:33: warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call
/Users/tkuah/code/ee-gdk/gitlab/lib/feature.rb:61: warning: The called method `enabled?' is defined here
/Users/tkuah/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/attr_encrypted-3.1.0/lib/attr_encrypted/adapters/active_record.rb:63: warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call
/Users/tkuah/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/activemodel-6.0.3.1/lib/active_model/dirty.rb:169: warning: The called method `attribute_changed?' is defined here
./Users/tkuah/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/activerecord-6.0.3.1/lib/active_record/relation.rb:412: warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call
/Users/tkuah/code/ee-gdk/gitlab/app/models/concerns/has_environment_scope.rb:25: warning: The called method is defined here
..

Finished in 2 minutes 50.6 seconds (files took 24.26 seconds to load)
3 examples, 0 failures