refactor!: update minimum Ruby version to 3.0

spec/rails_helper.rb

@@ -12,7 +12,7 @@ require 'rspec/rails'
 require 'capybara/rails'
 require 'rspec/retry'
 
-Dir[File.expand_path('support/**/*.rb', __dir__)].sort.each { |f| require f }
+Dir[File.expand_path('support/**/*.rb', __dir__)].each { |f| require f }
 
 # Force deprecations to raise an exception.
 ActiveSupport::Deprecation.behavior = :raise
@@ -27,7 +27,7 @@ rescue ActiveRecord::PendingMigrationError => e
 end
 
 RSpec.configure do |config|
-  config.fixture_path = "#{::Rails.root}/spec/fixtures"
+  config.fixture_path = Rails.root.join('spec/fixtures').to_s
   config.infer_spec_type_from_file_location!
   config.filter_rails_from_backtrace!