Bump puma from 3.12.0 to 3.12.2 (#3)

Bumps [puma](https://github.com/puma/puma) from 3.12.0 to 3.12.2.
- [Release notes](https://github.com/puma/puma/releases)
- [Changelog](https://github.com/puma/puma/blob/master/History.md)
- [Commits](puma/puma@v3.12.0...v3.12.2)

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

Author: dependabot[bot]

Gemfile

@@ -8,7 +8,7 @@ gem 'rails', '~> 5.2.1'
 # Use sqlite3 as the database for Active Record
 gem 'sqlite3'
 # Use Puma as the app server
-gem 'puma', '~> 3.11'
+gem 'puma', '~> 3.12'
 # Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
  gem 'jbuilder', '~> 2.5'
 # Use Redis adapter to run Action Cable in production

Gemfile.lock

@@ -81,7 +81,7 @@ GEM
     nio4r (2.3.1)
     nokogiri (1.10.5)
       mini_portile2 (~> 2.4.0)
-    puma (3.12.0)
+    puma (3.12.2)
     rack (2.0.6)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -144,7 +144,7 @@ DEPENDENCIES
   faker
   jbuilder (~> 2.5)
   listen (>= 3.0.5, < 3.2)
-  puma (~> 3.11)
+  puma (~> 3.12)
   rails (~> 5.2.1)
   spring
   spring-watcher-listen (~> 2.0.0)