Bump puma from 5.6.7 to 5.6.8

Bumps [puma](https://github.com/puma/puma) from 5.6.7 to 5.6.8.
- [Release notes](https://github.com/puma/puma/releases)
- [Changelog](https://github.com/puma/puma/blob/master/History.md)
- [Commits](puma/puma@v5.6.7...v5.6.8)

---
updated-dependencies:
- dependency-name: puma
  dependency-type: direct:production
...

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

Gemfile.lock

@@ -152,7 +152,7 @@ GEM
     psych (5.1.1.1)
       stringio
     public_suffix (5.0.4)
-    puma (5.6.7)
+    puma (5.6.8)
       nio4r (~> 2.0)
     racc (1.7.3)
     rack (2.2.8)