feat: Support weight in forward action

[alexbricepalo]

Description

Added a 'weighted-forward' dynamic action block to use with the https_listener_rules for multiple weighted target_group

Motivation and Context

This adds a dynamic action block for a "weighted-forward" action_rule.type for the https_listener_rules . It allows us to create a listener rule like:

{
  https_listener_index = 0
  priority             = 30

  actions = [
    {
      type = "weighted-forward"
      target_groups = [
        {
          target_group_index = 1
          weight             = 1
        },
        {
          target_group_index = 0
          weight             = 0
        }
      ]
    }
  ]

  conditions = [{}]
}

Fixes #211

Breaking Changes

No breaking changes

How Has This Been Tested?

• [√] I have tested and validated these changes using one or more of the provided examples/* projects

I created the resources and visually verified the correct rules made it onto the load balancer.

+ forward {
  + stickiness {
    + duration = 0
    + enabled  = false
  }
  
  + target_group {
    + arn    = "arn:aws:elasticloadbalancing:us-east-1:../f0eaf247061478b5"
    + weight = 1
  }
  + target_group {
    + arn    = "arn:aws:elasticloadbalancing:us-east-1:../9bb7dfca9e8b8565"
    + weight = 2
  }
}

[antonbabenko]

Looks good, but there is a bug in the provider (hashicorp/terraform-provider-aws#15144) and we need to come up with a workaround for it.

[antonbabenko]

Suggested change

	dynamic target_group {
	dynamic "target_group" {

[antonbabenko]

Please add support for stickiness as described here - https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/lb_listener_rule#stickiness

[antonbabenko]

Also, could you make sure that the example works when values in weight change?

Currently, terraform apply fails after changing it with this error:

│ Error: Error modifying LB Listener Rule: ValidationError: Target group stickiness duration must be between 1 and 604800 seconds

Here is a related bug - hashicorp/terraform-provider-aws#15144

[alexbricepalo]

Thank you @antonbabenko. I updated my PR and added the stickiness block.

[antonbabenko]

Thanks, @alexbricepalo !

v6.6.0 has been just released.

[github-actions]

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