Revert bump to 0.61.0

[zacharyweidenbach]

Currently an unresolved issue on 0.61.0 of the cloudposse/ecs-container-definition/aws repo

cloudposse/terraform-aws-ecs-container-definition#171

This makes the terraform plan command fail with this error

│ Error: Invalid type specification
│
│   on .terraform/modules/backend.service_container_definition/variables.tf line 107, in variable "container_definition":
│  102:     portMappings = optional(list(object({
│  103:       name          = optional(string)
│  104:       containerPort = number
│  105:       hostPort      = optional(number)
│  106:       protocol      = optional(string)
│  107:       name          = optional(string)
│  108:       appProtocol   = optional(string)
│  109:     })))
│
│ Object constructor map keys must be unique.