创建数据库实例时出错:InvalidParameterValue:PostgreSQL 数据库的数据库引擎无效

Error creating DB instance: InvalidParameterValue: Invalid DB engine for PostgreSQL DB

我正在尝试使用 Terraform 创建 PostgreSQL RDS 实例。 这是我的配置:

resource "aws_db_subnet_group" "postgres" {
   name = "postgres-subnets"
   subnet_ids = ["mysub1","mysub2"]
}    
resource "aws_db_instance" "myrds" {
   engine = "postgresql"
   engine_version = "12.4"
   instance_class = "db.t2.micro"
   identifier = "myrds"
   username = "myuser"
   password = "*******"
   allocated_storage = 10
   storage_type = "gp2"
   db_subnet_group_name = "${aws_db_subnet_group.postgres.id}"
}

失败并出现以下错误:

Error: Error creating DB Instance: InvalidParameterValue: Invalid DB engine

Terraform 文档需要添加支持的引擎名称: engine = "postgresql" 不正确。支持的值为 "postgres"