Bump json from 2.1.0 to 2.5.1 (#1)

Bumps [json](https://github.com/flori/json) from 2.1.0 to 2.5.1.
- [Release notes](https://github.com/flori/json/releases)
- [Changelog](https://github.com/flori/json/blob/master/CHANGES.md)
- [Commits](flori/json@v2.1.0...v2.5.1)

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Gemfile.lock

@@ -61,7 +61,7 @@ GEM
     httpclient (2.8.3)
     i18n (0.9.5)
       concurrent-ruby (~> 1.0)
-    json (2.1.0)
+    json (2.5.1)
     minitest (5.11.3)
     molinillo (0.6.6)
     nanaimo (0.2.6)