Bump puma from 5.6.2 to 5.6.4

Bumps [puma](https://github.com/puma/puma) from 5.6.2 to 5.6.4.
- [Release notes](https://github.com/puma/puma/releases)
- [Changelog](https://github.com/puma/puma/blob/master/History.md)
- [Commits](puma/puma@v5.6.2...v5.6.4)

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

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

Author: dependabot[bot]

Gemfile.lock

@@ -17,7 +17,7 @@ GEM
     mustermann (1.1.1)
       ruby2_keywords (~> 0.0.1)
     nio4r (2.5.8)
-    puma (5.6.2)
+    puma (5.6.4)
       nio4r (~> 2.0)
     rack (2.2.3)
     rack-attack (6.6.0)