.travis.yml in datadog-notifications-0.5.0 vs .travis.yml in datadog-notifications-0.5.1

@@ -1,6 +1,7 @@
 sudo: false
 language: ruby
 rvm:
-  - 2.4.0
-  - 2.3.3
-  - 2.2.6
+  - 2.5
+  - 2.4
+  - 2.3
+  - 2.2