Replace hack with track_latest attribute

[bryantbiggs]

Is your request related to a new offering from AWS?

Is this functionality available in the AWS provider for Terraform? See CHANGELOG.md, too.

• No 🛑: please wait to file a request until the functionality is avaialble in the AWS provider
• Yes ✅: please list the AWS provider version which introduced this functionality

Is your request related to a problem? Please describe.

• This ugly hack

  terraform-aws-ecs/modules/service/main.tf

  Lines 589 to 608 in 8b97783

  	# This allows us to query both the existing as well as Terraform's state and get
  	# and get the max version of either source, useful for when external resources
  	# update the container definition
  	max_task_def_revision = local.create_task_definition ? max(aws_ecs_task_definition.this[0].revision, data.aws_ecs_task_definition.this[0].revision) : 0
  	task_definition = local.create_task_definition ? "${aws_ecs_task_definition.this[0].family}:${local.max_task_def_revision}" : var.task_definition_arn
  	}
  	# This allows us to query both the existing as well as Terraform's state and get
  	# and get the max version of either source, useful for when external resources
  	# update the container definition
  	data "aws_ecs_task_definition" "this" {
  	count = local.create_task_definition ? 1 : 0
  	task_definition = aws_ecs_task_definition.this[0].family
  	depends_on = [
  	# Needs to exist first on first deployment
  	aws_ecs_task_definition.this
  	]
  	}

Describe the solution you'd like.

• r/aws_ecs_task_definition: add track_latest attribute hashicorp/terraform-provider-aws#30154

Describe alternatives you've considered.

Additional context