.travis.yml in async-io-1.12.2 vs .travis.yml in async-io-1.12.3

@@ -5,15 +5,15 @@
 
 before_script: 
   - gem update --system
   - gem install bundler
 
-
 matrix:
   include:
     - rvm: 2.3
     - rvm: 2.4
     - rvm: 2.5
+    - rvm: 2.6
     - rvm: jruby-head
       env: JRUBY_OPTS="--debug -X+O"
     - rvm: ruby-head
     - rvm: rbx-3
   allow_failures: