Bump puma from 4.3.6 to 4.3.9 in /preview

Bumps [puma](https://github.com/puma/puma) from 4.3.6 to 4.3.9.
- [Release notes](https://github.com/puma/puma/releases)
- [Changelog](https://github.com/puma/puma/blob/master/History.md)
- [Commits](puma/puma@v4.3.6...v4.3.9)

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

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

preview/Gemfile

@@ -6,7 +6,7 @@ ruby '3.0.0'
 # Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
 gem 'rails', '~> 6.0.3', '>= 6.0.3.4'
 # Use Puma as the app server
-gem 'puma', '~> 4.1'
+gem 'puma', '~> 4.3'
 # Transpile app-like JavaScript. Read more: https://github.com/rails/webpacker
 gem 'webpacker', '~> 4.0'
 

preview/Gemfile.lock

@@ -89,11 +89,11 @@ GEM
     mini_portile2 (2.6.1)
     minitest (5.14.2)
     msgpack (1.3.3)
-    nio4r (2.5.4)
+    nio4r (2.5.8)
     nokogiri (1.12.5)
       mini_portile2 (~> 2.6.1)
       racc (~> 1.4)
-    puma (4.3.6)
+    puma (4.3.9)
       nio4r (~> 2.0)
     racc (1.6.0)
     rack (2.2.3)
@@ -173,7 +173,7 @@ DEPENDENCIES
   bootsnap (>= 1.4.2)
   byebug
   listen (~> 3.2)
-  puma (~> 4.1)
+  puma (~> 4.3)
   rails (~> 6.0.3, >= 6.0.3.4)
   responders
   spring