.travis.yml in async-io-1.3.0 vs .travis.yml in async-io-1.4.0

@@ -3,14 +3,13 @@
 dist: trusty
 cache: bundler
 
 matrix:
   include:
-    - rvm: 2.0
-    - rvm: 2.1
     - rvm: 2.2
     - rvm: 2.3
     - rvm: 2.4
+    - rvm: 2.5
     - rvm: jruby-head
       env: JRUBY_OPTS="--debug -X+O"
     - rvm: ruby-head
     - rvm: rbx-3
   allow_failures: