Changes

• Add route grouping and scope specific middlewares.
• Accepts interfaces in grape.Options struct. Allowing for better customizability.
• Any types implementing grape.Logger, including slog.Logger, can be used for logging.
• Use grape.Serializer to configure reading and writing json.
• Optionally, specify requests' max body size.
• Improvements to the validator package.
• New example, graceful shutdown.
• Improve documentation and update examples.