Update responders to version 2.3.0

Author: sferik

Gemfile.lock

@@ -158,7 +158,7 @@ GEM
     rainbow (2.1.0)
     rake (11.3.0)
     remotipart (1.3.0)
-    responders (2.2.0)
+    responders (2.3.0)
       railties (>= 4.2.0, < 5.1)
     rubocop (0.41.2)
       parser (>= 2.3.1.1, < 3.0)