update travis.yml

.travis.yml

@@ -1,17 +1,17 @@
 language: ruby
+
 sudo: false
+
+rvm:
+  - 2.3
+  - 2.4
+  - 2.5
+  - 2.6
+  - ruby-head
+
 before_install: gem install bundler
-env: SUITE="rspec"
-script: bundle exec $SUITE
+
 matrix:
   fast_finish: true
-  include:
-  - rvm: 2.3
-  - rvm: 2.4
-  - rvm: 2.5
-  - rvm: 2.6
-  - rvm: 2.6 # Only run RuboCop on the latest Ruby
-    env: SUITE="rubocop"
-  - rvm: ruby-head
   allow_failures:
-  - rvm: ruby-head
+    - rvm: ruby-head

Rakefile

@@ -17,4 +17,4 @@ end
 
 RSpec::Core::RakeTask.new(:rspec)
 
-task default: :rspec
+task default: %i[rubocop rspec]