Changes to Create migration

added the new scheduled enum value to the data/strategy response property for the response status 201

added the new optional request property scheduled_at

added the new scheduled enum value to the request property strategy

added the optional property data/scheduled_at to the response with the 201 status

added the optional property data/feature_id to the response with the 201 status

added the optional property data/feature_plan_rollout_id to the response with the 201 status

added the new cancelled enum value to the data/status response property for the response status 201

added the new end_of_billing_period enum value to the data/strategy response property for the response status 201

added the new end_of_billing_period enum value to the request property strategy

added the optional property data/next_due_at to the response with the 201 status

added the new none enum value to the data/proration_behavior/allOf[#/components/schemas/MigrationProrationBehavior] response property for the response status 201

added the new none enum value to the request property proration_behavior/allOf[#/components/schemas/MigrationProrationBehavior]

the request property company_ids became optional

the request property excluded_company_ids became optional

the request property plan_version_ids_from became optional

added the new optional request property proration_behavior

added the optional property data/proration_behavior to the response with the 201 status

endpoint added