Support Rails 7.
Note: Sprockets is no longer an explicit dependency in Rails 7, so if your application still uses Sprockets (or Propshaft) then that railtie will now be loaded by Bundler.require(*Rails.groups) in config/application.rb (rather than by require "rails/all"). As a result, it's important to place the require "external_asset_pipeline/railtie" line after Bundler.require(*Rails.groups) to ensure that ExternalAssetPipeline takes precedence over Sprockets (or Propshaft).