Bump puma from 4.3.1 to 4.3.3 in /examples/simple_rails_api

Bumps [puma](https://github.com/puma/puma) from 4.3.1 to 4.3.3.
- [Release notes](https://github.com/puma/puma/releases)
- [Changelog](https://github.com/puma/puma/blob/master/History.md)
- [Commits](puma/puma@v4.3.1...v4.3.3)

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

examples/simple_rails_api/Gemfile

@@ -6,7 +6,7 @@ gem 'rails', '~> 6.0.2'
 # Use sqlite3 as the database for Active Record
 gem 'sqlite3', '~> 1.4'
 # Use Puma as the app server
-gem 'puma', '~> 4.1'
+gem 'puma', '~> 4.3'
 # Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
 # gem 'jbuilder', '~> 2.7'
 # Use Redis adapter to run Action Cable in production

examples/simple_rails_api/Gemfile.lock

@@ -88,7 +88,7 @@ GEM
     nio4r (2.5.2)
     nokogiri (1.10.8)
       mini_portile2 (~> 2.4.0)
-    puma (4.3.1)
+    puma (4.3.3)
       nio4r (~> 2.0)
     rack (2.2.2)
     rack-test (1.1.0)
@@ -152,7 +152,7 @@ DEPENDENCIES
   bootsnap (>= 1.4.2)
   byebug
   listen (>= 3.0.5, < 3.2)
-  puma (~> 4.1)
+  puma (~> 4.3)
   rails (~> 6.0.2)
   spring
   spring-watcher-listen (~> 2.0.0)