Bump puma from 3.11.0 to 3.12.6

Bumps [puma](https://github.com/puma/puma) from 3.11.0 to 3.12.6.
- [Release notes](https://github.com/puma/puma/releases)
- [Changelog](https://github.com/puma/puma/blob/master/History.md)
- [Commits](https://github.com/puma/puma/commits)

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

Gemfile

@@ -14,7 +14,7 @@ gem 'whenever', require: false
 gem 'bcrypt', '~> 3.1.7'
 gem 'has_secure_token'
 
-gem 'puma', '~> 3.7'
+gem 'puma', '~> 3.12'
 
 gem 'bugsnag'
 gem 'snitcher'

Gemfile.lock

@@ -161,7 +161,7 @@ GEM
       arel (>= 6)
     powerpack (0.1.1)
     public_suffix (3.0.1)
-    puma (3.11.0)
+    puma (3.12.6)
     rack (2.0.8)
     rack-protection (2.0.5)
       rack
@@ -315,7 +315,7 @@ DEPENDENCIES
   ougai
   pg (~> 0.20.0)
   pg_search
-  puma (~> 3.7)
+  puma (~> 3.12)
   rails (~> 5.1.4)
   redis-rails
   rubocop