Align ruby and rails support with the main doorkeeper gem

.ruby-version

@@ -1 +1 @@
-2.7.2
+3.1.2

doorkeeper-openid_connect.gemspec

@@ -22,7 +22,7 @@ Gem::Specification.new do |spec|
   spec.executables   = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }
   spec.require_paths = ['lib']
 
-  spec.required_ruby_version = '>= 2.5'
+  spec.required_ruby_version = '>= 2.6'
 
   spec.add_runtime_dependency 'doorkeeper', '>= 5.5', '< 5.7'
   spec.add_runtime_dependency 'json-jwt', '>= 1.11.0'

spec/dummy/config/database.yml

@@ -4,22 +4,23 @@
 #   Ensure the SQLite 3 gem is defined in your Gemfile
 #   gem 'sqlite3'
 #
-default: &default
+development:
   adapter: sqlite3
   pool: 5
   timeout: 5000
-
-development:
-  <<: *default
   database: db/development.sqlite3
 
 # Warning: The database defined as "test" will be erased and
 # re-generated from your development database when you run "rake".
 # Do not set this db to the same as development or production.
 test:
-  <<: *default
+  adapter: sqlite3
+  pool: 5
+  timeout: 5000
   database: db/test.sqlite3
 
 production:
-  <<: *default
+  adapter: sqlite3
+  pool: 5
+  timeout: 5000
   database: db/production.sqlite3

spec/rails_helper.rb

@@ -30,9 +30,6 @@
   ActiveRecord::Migration.maintain_test_schema!
 end
 
-# Remove after dropping support of Rails 4.2
-require_relative 'support/http_method_shim.rb'
-
 require_relative 'support/doorkeeper_configuration.rb'
 
 require 'factory_bot'