Bump puma from 3.12.2 to 4.3.1 in /source/scripts/ruby/blog/source

Bumps [puma](https://github.com/puma/puma) from 3.12.2 to 4.3.1.
- [Release notes](https://github.com/puma/puma/releases)
- [Changelog](https://github.com/puma/puma/blob/master/History.md)
- [Commits](puma/puma@v3.12.2...v4.3.1)

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

source/scripts/ruby/blog/source/Gemfile

@@ -11,7 +11,7 @@ gem 'rails', '~> 5.0.1'
 # Use sqlite3 as the database for Active Record
 gem 'sqlite3'
 # Use Puma as the app server
-gem 'puma', '~> 3.12'
+gem 'puma', '~> 4.3'
 # Use SCSS for stylesheets
 gem 'sass-rails', '~> 5.0'
 # Use Uglifier as compressor for JavaScript assets

source/scripts/ruby/blog/source/Gemfile.lock

@@ -79,7 +79,8 @@ GEM
     nio4r (2.4.0)
     nokogiri (1.10.5)
       mini_portile2 (~> 2.4.0)
-    puma (3.12.2)
+    puma (4.3.1)
+      nio4r (~> 2.0)
     rack (2.0.8)
     rack-test (0.6.3)
       rack (>= 1.0)
@@ -162,7 +163,7 @@ DEPENDENCIES
   jbuilder (~> 2.5)
   jquery-rails
   listen (~> 3.0.5)
-  puma (~> 3.12)
+  puma (~> 4.3)
   rails (~> 5.0.1)
   sass-rails (~> 5.0)
   spring