Bump json from 2.15.2 to 2.15.2.1 in /examples/ruby

Bumps [json](https://github.com/ruby/json) from 2.15.2 to 2.15.2.1.
- [Release notes](https://github.com/ruby/json/releases)
- [Changelog](https://github.com/ruby/json/blob/master/CHANGES.md)
- [Commits](ruby/json@v2.15.2...v2.15.2.1)

---
updated-dependencies:
- dependency-name: json
  dependency-version: 2.15.2.1
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

examples/ruby/Gemfile.lock

@@ -4,7 +4,7 @@ GEM
     ast (2.4.3)
     base64 (0.3.0)
     diff-lcs (1.5.1)
-    json (2.15.2)
+    json (2.15.2.1)
     language_server-protocol (3.17.0.5)
     lint_roller (1.1.0)
     logger (1.7.0)