.travis.yml in amq-protocol-2.3.0 vs .travis.yml in amq-protocol-2.3.1

@@ -1,13 +1,15 @@
+dist: bionic
 language: ruby
 bundler_args: --without development
 cache: bundler
 script: "bundle exec rspec spec"
 rvm:
   - ruby-head
-  - "2.4.1"
-  - "2.3.4"
-  - "2.2.7"
+  - "2.6.3"
+  - "2.5.5"
+  - "2.4.5"
+  - "2.3.8"
 notifications:
   recipients:
     - [e-mail]
 matrix:
   allow_failures: