resource/aws_eks_cluster: allow referencing arn attribute

[razaj92]

Fixes #4764

Changes proposed in this pull request:

• expose arn in resource aws_eks_cluster
• expose arn in data aws_eks_cluster

Output from acceptance testing:

$ make testacc TESTARGS='-run=TestAccAWSEksCluster_basic'
==> Checking that code complies with gofmt requirements...
TF_ACC=1 go test ./... -v -run=TestAccAWSEksCluster_basic -timeout 120m
?   	github.com/terraform-providers/terraform-provider-aws	[no test files]
=== RUN   TestAccAWSEksCluster_basic
--- PASS: TestAccAWSEksCluster_basic (785.40s)
PASS
ok  	github.com/terraform-providers/terraform-prov
...

[bflad]

Thanks for submitting this @razaj92! Unfortunately we submitted around the same time and the fix from #4766 landed first. 😅 Good news is that this will be fixed in version 1.23.0 of the AWS provider.

[ghost]

I'm going to lock this issue because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.

If you feel this issue should be reopened, we encourage creating a new issue linking back to this one for added context. Thanks!