Enable Rails 7.1 Marshalling format (#28609)

config/application.rb

@@ -63,6 +63,8 @@ module Mastodon
     # Initialize configuration defaults for originally generated Rails version.
     config.load_defaults 7.0
 
+    config.active_record.marshalling_format_version = 7.1
+
     # Please, add to the `ignore` list any other `lib` subdirectories that do
     # not contain `.rb` files, or that should not be reloaded or eager loaded.
     # Common ones are `templates`, `generators`, or `middleware`, for example.