.travis.yml in twilio-ruby-5.10.7 vs .travis.yml in twilio-ruby-5.11.0

@@ -3,14 +3,13 @@
 cache: bundler
 bundler_args: --without development
 
 rvm:
   - ruby-head
+  - 2.5.0
   - 2.4.0
   - 2.3.0
   - 2.2.0
-  - 2.1
-  - 2.0.0
   - jruby-9.1.9.0
 
 services:
   - docker