HCL2 vault_aws_engine

Hi, having an issue with the HCL2 formatted files. I’m converting a working json file to hcl, and using vault as part of the build. When converting the file it puts in an entry for the AWS authentication

data "amazon-ami" "ubuntu" {
  filters = {
    name                = "ubuntu-minimal/images/hvm-ssd/ubuntu-bionic-18.04-amd64-minimal-*"
    root-device-type    = "ebs"
    virtualization-type = "hvm"
  }
  most_recent = true
  owners      = ["aws-marketplace"]
  region      = "eu-west-1"
  vault_aws_engine = {
    name = "myrole"
  }
}

Unfortunately it throws this error when I validate the file:

Error: Unsupported argument

  on base.pkr.hcl line 44:
  (source code not available)

An argument named "vault_aws_engine" is not expected here. Did you mean to
define a block of type "vault_aws_engine"?

Thought maybe it was the plugins, which I’ve added, but it still throws the error even when they are installed.

packer {
  required_plugins {
    amazon = {
      version = "= 1.0.7"
      source  = "github.com/hashicorp/amazon"
    }
    inspec = {
      version = "= 1.0.0"
      source  = "github.com/hashicorp/inspec"
    }
    ansible = {
      version = "= 1.0.1"
      source  = "github.com/hashicorp/ansible"
    }
  }
}

Any help appreciated.

D