Bump puma from 3.12.1 to 3.12.2 (#887)

Bumps [puma](https://github.com/puma/puma) from 3.12.1 to 3.12.2.
- [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/v3.12.1...v3.12.2)

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

Gemfile

@@ -11,7 +11,7 @@ end
 gem 'rails', '~> 5.2.3'
 
 # Use Puma as the app server
-gem 'puma', '~> 3.0'
+gem 'puma', '~> 3.12'
 
 # Use SCSS for stylesheets
 gem 'sassc-rails'

Gemfile.lock

@@ -214,7 +214,7 @@ GEM
     pg (0.21.0)
     popper_js (1.14.5)
     public_suffix (3.1.1)
-    puma (3.12.1)
+    puma (3.12.2)
     rack (2.0.7)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -378,7 +378,7 @@ DEPENDENCIES
   omniauth-twitter
   pagy
   pg (~> 0.18)
-  puma (~> 3.0)
+  puma (~> 3.12)
   rails (~> 5.2.3)
   rails-controller-testing
   random_password