.travis.yml in commander-4.6.0 vs .travis.yml in commander-5.0.0

@@ -2,12 +2,11 @@
 cache: bundler
 before_install:
   - gem update --system
   - gem update bundler
 rvm:
-  - 2.4
-  - 2.5
-  - 2.6
-  - 2.7
   - 3.0
+  - 3.1
+  - 3.2
+  - 3.3
   - jruby
   - ruby-head