Update jquery-rails to version 4.2.1

Author: sferik

Diff for: Gemfile.lock

@@ -77,7 +77,7 @@ GEM
     hashdiff (0.3.0)
     http_accept_language (2.0.5)
     i18n (0.7.0)
-    jquery-rails (4.1.1)
+    jquery-rails (4.2.1)
       rails-dom-testing (>= 1, < 3)
       railties (>= 4.2.0)
       thor (>= 0.14, < 2.0)