Bump json version to support ruby 2.4.0

nougad · web-flow · commit 82d665208f1b · 2017-01-16T21:59:22.000+01:00
json 1.8.3 fails because of ruby/json#286
diff --git a/Gemfile.lock b/Gemfile.lock
@@ -18,7 +18,7 @@ GEM
     faraday (0.9.2)
       multipart-post (>= 1.2, < 3)
     i18n (0.7.0)
-    json (1.8.3)
+    json (1.8.6)
     json-jwt (1.5.2)
       activesupport
       bindata
