Bump puma from 3.12.2 to 3.12.4 in /builder

Bumps [puma](https://github.com/puma/puma) from 3.12.2 to 3.12.4.
- [Release notes](https://github.com/puma/puma/releases)
- [Changelog](https://github.com/puma/puma/blob/master/History.md)
- [Commits](puma/puma@v3.12.2...v3.12.4)

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

Author: dependabot[bot]

builder/Gemfile

@@ -6,7 +6,7 @@ ruby '2.6.5'
 # Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
 gem 'rails', '~> 5.2.0'
 # Use Puma as the app server
-gem 'puma', '~> 3.11'
+gem 'puma', '~> 3.12'
 # Use SCSS for stylesheets
 gem 'sass-rails', '~> 5.0'
 # Use Uglifier as compressor for JavaScript assets

builder/Gemfile.lock

@@ -86,7 +86,7 @@ GEM
     nio4r (2.5.2)
     nokogiri (1.10.7)
       mini_portile2 (~> 2.4.0)
-    puma (3.12.2)
+    puma (3.12.4)
     rack (2.1.2)
     rack-proxy (0.6.5)
       rack
@@ -168,7 +168,7 @@ DEPENDENCIES
   coffee-rails (~> 4.2)
   jbuilder (~> 2.5)
   listen (>= 3.0.5, < 3.2)
-  puma (~> 3.11)
+  puma (~> 3.12)
   rails (~> 5.2.0)
   sass-rails (~> 5.0)
   tzinfo-data