.travis.yml in squib-0.12.0 vs .travis.yml in squib-0.13.0

@@ -9,10 +9,11 @@
     packages:
       - libgirepository1.0-dev # for gobject-introspection
 
 rvm:
   - 2.2
+  - 2.3.2
   - 2.3.3
-  - 2.4.0-preview3
+  - 2.4.0
 matrix:
   allow_failures:
-    - rvm: 2.4.0-preview3
+    - rvm: 2.3.3