[Security] Bump json from 2.1.0 to 2.3.0

Bumps [json](https://github.com/flori/json) from 2.1.0 to 2.3.0. **This update includes a security fix.**
- [Release notes](https://github.com/flori/json/releases)
- [Changelog](https://github.com/flori/json/blob/master/CHANGES.md)
- [Commits](ruby/json@v2.1.0...v2.3.0)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Gemfile.lock

@@ -205,7 +205,7 @@ GEM
       rails-dom-testing (>= 1, < 3)
       railties (>= 4.2.0)
       thor (>= 0.14, < 2.0)
-    json (2.1.0)
+    json (2.3.0)
     kaminari (0.15.1)
       actionpack (>= 3.0.0)
       activesupport (>= 3.0.0)