.travis.yml in cloudtasker-0.8.0 vs .travis.yml in cloudtasker-0.8.1

@@ -1,13 +1,13 @@
 ---
 language: ruby
 cache: bundler
 rvm:
-  - 2.3
-  - 2.4
   - 2.5.5
+services:
+  - redis-server
 before_install: gem install bundler -v 2.0.2
-before_script: rubocop
+before_script: bundle exec rubocop
 gemfile:
   - gemfiles/google_cloud_tasks_1.0.gemfile
   - gemfiles/google_cloud_tasks_1.1.gemfile
   - gemfiles/google_cloud_tasks_1.2.gemfile
   - gemfiles/google_cloud_tasks_1.3.gemfile