.travis.yml in fb_graph2-0.7.9 vs .travis.yml in fb_graph2-0.8.0

- old
+ new

@@ -1,8 +1,7 @@
 before_install:
   - gem install bundler
 
 rvm:
-  - 2.0
-  - 2.1
-  - 2.2
-  - 2.3.0
+  - 2.2.2 # NOTE: 2.2.1 or lower aren't supported by activesupport 5.0, CI isn't needed for such legacy versions.
+  - 2.2.5
+  - 2.3.1
\ No newline at end of file