Bump puma from 6.4.2 to 6.4.3

Bumps [puma](https://github.com/puma/puma) from 6.4.2 to 6.4.3.
- [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/v6.4.2...v6.4.3)

---
updated-dependencies:
- dependency-name: puma
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Gemfile.lock

@@ -166,7 +166,7 @@ GEM
     psych (5.1.2)
       stringio
     public_suffix (6.0.1)
-    puma (6.4.2)
+    puma (6.4.3)
       nio4r (~> 2.0)
     racc (1.8.1)
     rack (3.1.7)