.travis.yml in sidekiq-cron-0.6.3 vs .travis.yml in sidekiq-cron-1.0.0

@@ -1,8 +1,10 @@
 language: ruby
 rvm:
-  - 2.3.1
-  - 2.2.2
+  - 2.5.0
+  - 2.4.3
+  - 2.3.6
+  - 2.2.9
 services:
   - redis-server
 branches:
   only:
     - master