Bump puma from 5.6.8 to 5.6.9

Bumps [puma](https://github.com/puma/puma) from 5.6.8 to 5.6.9.
- [Release notes](https://github.com/puma/puma/releases)
- [Changelog](https://github.com/puma/puma/blob/master/History.md)
- [Commits](https://github.com/puma/puma/compare/v5.6.8...v5.6.9)

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

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

Gemfile.lock

@@ -424,7 +424,7 @@ GEM
     psych (5.1.2)
       stringio
     public_suffix (6.0.1)
-    puma (5.6.8)
+    puma (5.6.9)
       nio4r (~> 2.0)
     quad_tile (1.0.1)
     racc (1.8.1)