Bump puma from 4.2.0 to 4.2.1

Bumps [puma](https://github.com/puma/puma) from 4.2.0 to 4.2.1.
- [Release notes](https://github.com/puma/puma/releases)
- [Changelog](https://github.com/puma/puma/blob/master/History.md)
- [Commits](puma/puma@v4.2.0...v4.2.1)

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

Gemfile.lock

@@ -221,7 +221,7 @@ GEM
       cliver (~> 0.3.1)
       websocket-driver (>= 0.2.0)
     public_suffix (4.0.1)
-    puma (4.2.0)
+    puma (4.2.1)
       nio4r (~> 2.0)
     rabl (0.14.2)
       activesupport (>= 2.3.14)