AssumeRoleConfig lets users set configuration options for assuming a special role when executing Packer. Usage example: HCL config example: ```HCL source "example" "amazon-ebs"{ assume_role { role_arn = "arn:aws:iam::ACCOUNT_ID:role/ROLE_NAME" session_name = "SESSION_NAME" external_id = "EXTERNAL_ID" } } ``` JSON config example: ```json builder{ "type": "amazon-ebs", "assume_role": { "role_arn" : "arn:aws:iam::ACCOUNT_ID:role/ROLE_NAME", "session_name": "SESSION_NAME", "external_id" : "EXTERNAL_ID" } } ```