Test with Ruby 2.7

Author: rafaelfranca

.travis.yml

@@ -9,16 +9,16 @@ before_install: gem install bundler -v '<2'
 rvm:
   - 2.5.3
   - 2.6.0
+  - 2.7.1
   - jruby-9.2.5.0
   - jruby-head
   - ruby-head
 
 matrix:
   include:
-    - rvm: 2.6.0
+    - rvm: 2.7.1
       script: bundle exec rake test_isolated
-  include:
-    - rvm: 2.6.0
+    - rvm: 2.7.1
       script: bundle exec rake rubocop
   allow_failures:
     - rvm: jruby-9.2.5.0