feat: Add arn of created group(s) to outputs

[soupdiver]

Description

Export arn of created groups

Motivation and Context

We have multiple AWS accounts across our org. IAM user are kept centrally in one account, are put into groups and the groups get permission to assumeRole in other accounts. We need the group arn for the trustee relationship between the accounts.

How Has This Been Tested?

I run Terraform from my branch and compared the result.

Before:

Unsupported attribute

  on outputs.tf line 5, in output "groups":
   5:       arn   = module.iam-groups[name]. group_arn
    |----------------
    | module.iam-groups is object with 3 attributes

This object does not have an attribute named "group_arn".

After:

Changes to Outputs:
  + groups = [
      + {
          + arn  = (known after apply)
          + name = "data-services-admin"
        },
      + {
          + arn  = (known after apply)
          + name = "data-services-developer"
        },
      + {
          + arn  = (known after apply)
          + name = "zeppelin-admin"
        },
    ]

[antonbabenko]

Thanks @soupdiver !

v3.8.0 has been just released.

[github-actions]

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