Update rails version and switch to public:true from active_storage

[github-actions]

config.action_cable.mount_path = nil

https://api.github.com/OpenSourcePolitics/decidim-mel/blob/7500e176432b625b3f298ead94dc70190a64c232/config/environments/production.rb#L40

  # config.action_dispatch.x_sendfile_header = 'X-Accel-Redirect' # for NGINX

  # Store uploaded files on the local file system (see config/storage.yml for options)
  config.active_storage.service = Rails.application.secrets.dig(:scaleway, :id).blank? ? :local : :scaleway

  # By default, files uploaded to Active Storage will be served from a private URL.
  # in production, you'll want to set this to :public so that files are served
  # unfortunately, this is not working with the current version of ActiveStorage
  # TODO: Update rails version and switch to public:true from active_storage
  config.active_storage.service_urls_expire_in = ENV.fetch("SERVICE_URLS_EXPIRE_IN") do
    if Rails.application.secrets.dig(:scaleway, :id).blank?
      "120000"
    else
      "1"
    end
  end.to_i.weeks

  # Mount Action Cable outside main process or domain
  # config.action_cable.mount_path = nil