Add conditional container_port for service registry for A records (#42)

Fixes issue where no SRV record in service disvocery dns config
causes the service_registries block in the aws_ecs_service resource
to fail because it does not accept container_port parameter

main.tf

@@ -208,7 +208,7 @@ resource "aws_ecs_service" "service" {
     for_each = var.service_registry_arn == "" ? [] : [1]
     content {
       registry_arn   = var.service_registry_arn
-      container_port = var.task_container_port
+      container_port = var.with_service_discovery_srv_record ? var.task_container_port : null
       container_name = var.container_name != "" ? var.container_name : var.name_prefix
     }
   }

variables.tf

@@ -144,7 +144,6 @@ variable "repository_credentials" {
   type        = string
 }
 
-
 variable "repository_credentials_kms_key" {
   default     = "alias/aws/secretsmanager"
   description = "key id, key ARN, alias name or alias ARN of the key that encrypted the repository credentials"
@@ -157,6 +156,12 @@ variable "service_registry_arn" {
   type        = string
 }
 
+variable "service_discovery_srv_record" {
+  default     = true
+  type        = bool
+  description = "Set to false if you specify a SRV DNS record in aws_service_discovery_service. If only A record, set this to false."
+}
+
 variable "stop_timeout" {
   description = "Time duration (in seconds) to wait before the container is forcefully killed if it doesn't exit normally on its own. On Fargate the maximum value is 120 seconds."
   default     = 30