Bump puma from 5.6.4 to 5.6.8

Bumps [puma](https://github.com/puma/puma) from 5.6.4 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@v5.6.4...v5.6.8)

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

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

Gemfile.lock

@@ -196,15 +196,15 @@ GEM
     modulejs-rails (2.2.0.0)
       railties (>= 4.0)
     multipart-post (2.1.1)
-    nio4r (2.5.8)
+    nio4r (2.7.0)
     nokogiri (1.13.10)
       mini_portile2 (~> 2.8.0)
       racc (~> 1.4)
     parallel (1.20.1)
     parser (3.0.1.1)
       ast (~> 2.4.1)
     public_suffix (5.0.0)
-    puma (5.6.4)
+    puma (5.6.8)
       nio4r (~> 2.0)
     racc (1.6.1)
     rack (2.2.6.3)