Added Ruby 2.6 and bumped latest minor ruby releases for 2.3, 2.4 and 2.5.

Author: skunkworker

.travis.yml

@@ -3,8 +3,9 @@ language: ruby
 bundler_args: "--binstubs --standalone --without documentation --path ../bundle"
 script: "bundle exec rake test"
 rvm:
-  - 2.3.7
-  - 2.4.4
-  - 2.5.1
+  - 2.3.8
+  - 2.4.5
+  - 2.5.3
+  - 2.6.1
 notifications:
   email: false