.travis.yml in feedjira-2.2.0 vs .travis.yml in feedjira-3.0.0.beta1

@@ -1,12 +1,12 @@
 language: ruby
 
 cache: bundler
 
 rvm:
-  - 2.1
   - 2.2
   - 2.3
+  - 2.4
   - jruby-9
   - ruby-head
 
 env:
   - HANDLER=nokogiri