Update travis-ci.yml

Author: kzaitsev

.travis.yml

@@ -1,21 +1,30 @@
+language: ruby
+
+sudo: false
+
 before_install:
   - gem update --system
   - gem install bundler
 
 rvm:
-  - 2.4.0
-  - 2.3.3
-  - 2.2.6
+  - 2.4.2
+  - 2.3.5
 
 matrix:
   fast_finish: true
 
   include:
+    - rvm: 2.2.8
+      env:
     - rvm: ruby-head
+      env:
     - rvm: jruby-head
+      env:
     - rvm: rbx-2
+      env:
 
   allow_failures:
+    - rvm: 2.2.8
     - rvm: ruby-head
     - rvm: jruby-head
     - rvm: rbx-2