.travis.yml in rib-1.5.1 vs .travis.yml in rib-1.5.2

- old
+ new

@@ -10,10 +10,10 @@
 
 matrix:
   include:
     - rvm: 2.2.5
     - rvm: 2.3.2
-    - rvm: 2.4.0
+    - rvm: 2.4.1
     - rvm: jruby-9
       env: JRUBY_OPTS=--debug
     - rvm: rbx
 
   allow_failures: