Add patch version back to Travis config

It did not like that they were missing

Author: codeodor

.travis.yml

@@ -1,8 +1,8 @@
 language: ruby
 sudo: false
 rvm:
-  - 2.2
-  - 2.3
+  - 2.2.5
+  - 2.3.1
 script: bundle exec rspec
 env:
   - PAGINATOR=kaminari