.travis.yml in fluent-plugin-gcloud-pubsub-custom-1.3.1 vs .travis.yml in fluent-plugin-gcloud-pubsub-custom-1.3.2

@@ -1,12 +1,10 @@
 language: ruby
 
 rvm:
-  - 2.1
-  - 2.2
-  - 2.3.6
-  - 2.4.3
-  - 2.5.0
+  - 2.4.6
+  - 2.5.5
+  - 2.6.3
   - ruby-head
 
 gemfile:
  - Gemfile