type: :aruba is no longer necessary

.rubocop.yml

@@ -49,3 +49,6 @@ RSpec/ContextWording:
     - with
     - within
     - for
+
+RSpec/DescribeClass:
+  Enabled: false

spec/error_message_spec.rb

@@ -1,4 +1,4 @@
-describe 'Show error message', type: :aruba do
+describe 'Show error message' do
   context 'when invalid option' do
     before { run_rf('--invalid-option') }
 

spec/filter/json_spec.rb

@@ -1,4 +1,4 @@
-describe 'JSON filter', type: :aruba do
+describe 'JSON filter' do
   context 'when -t option' do
     describe 'Output string' do
       let(:input) { load_fixture('json/string.json') }

spec/filter/text_spec.rb

@@ -1,4 +1,4 @@
-describe 'Text filter', type: :aruba do
+describe 'Text filter' do
   let(:input) do
     <<~INPUT
       1 foo

spec/filter/yaml_spec.rb

@@ -1,4 +1,4 @@
-describe 'YAML filter', type: :aruba do
+describe 'YAML filter' do
   context 'when use -t option' do
     describe 'Output string' do
       let(:input) { load_fixture('yaml/string.yml') }

spec/help_spec.rb

@@ -1,4 +1,4 @@
-describe 'Show help text', type: :aruba do
+describe 'Show help text' do
   let(:help_text) do
     <<~TEXT
       Usage: rf [options] 'command' file ...