build(deps): bump puma from 3.11.4 to 3.12.0

Bumps [puma](https://github.com/puma/puma) from 3.11.4 to 3.12.0.
- [Release notes](https://github.com/puma/puma/releases)
- [Changelog](https://github.com/puma/puma/blob/master/History.md)
- [Commits](puma/puma@v3.11.4...v3.12.0)

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

Gemfile

@@ -28,7 +28,7 @@ group :test, :production do
 end
 
 # Use Puma as the app server
-gem 'puma', '~> 3.7'
+gem 'puma', '~> 3.12'
 # Use SCSS for stylesheets
 gem 'sass-rails', '~> 5.0'
 # Use Uglifier as compressor for JavaScript assets

Gemfile.lock

@@ -107,7 +107,7 @@ GEM
       mini_portile2 (~> 2.3.0)
     pg (1.0.0)
     public_suffix (3.0.2)
-    puma (3.11.4)
+    puma (3.12.0)
     rack (2.0.5)
     rack-test (1.0.0)
       rack (>= 1.0, < 3)
@@ -209,7 +209,7 @@ DEPENDENCIES
   listen (>= 3.0.5, < 3.2)
   mysql2
   pg
-  puma (~> 3.7)
+  puma (~> 3.12)
   rails (~> 5.2.0)
   sass-rails (~> 5.0)
   selenium-webdriver