bump rails version in openapi3 rails example

examples/openapi3_rails/Gemfile

@@ -4,7 +4,7 @@ git_source(:github) { |repo| "https://github.com/#{repo}.git" }
 ruby '3.2.0'
 
 # Bundle edge Rails instead: gem 'rails', github: 'rails/rails', branch: 'main'
-gem 'rails', '~> 7.0.4.2'
+gem 'rails', '~> 7.0.8.1'
 # Use sqlite3 as the database for Active Record
 gem 'sqlite3', '~> 1.4'
 # Use Puma as the app server