.travis.yml in undercover-0.3.0 vs .travis.yml in undercover-0.3.1

@@ -1,11 +1,12 @@
 language: ruby
 rvm:
-  - 2.5.3
+  - 2.6.2
+  - 2.5.5
   - 2.4.5
-  - 2.3.8
+  - 2.3.7
 before_install:
-  - gem install bundler undercover
+  - gem install bundler undercover --no-doc
   - gem update --system
 script:
   - bundle exec rake
   - git pull origin master:master
   - undercover --compare master