Changes to Get clusters

the items/created_by_user_id response's property type changed from string to object for status 200

the items/image response's property type changed from string to object for status 200

the items/ip response's property type changed from string to object for status 200

the items/os_name response's property type changed from string to object for status 200

the items/startup_script_id response's property type changed from string to object for status 200

added the required property items/tags to the response with the 200 status