Support the new IAM for GKE with Workload Identity Federation

[yashwanth-l]

TL;DR

Google Cloud IAM policies can directly reference GKE workloads and Kubernetes service accounts as described in the recently announced blog: https://cloud.google.com/blog/products/identity-security/make-iam-for-gke-easier-to-use-with-workload-identity-federation

Terraform Resources

The resources declared in the module:
https://github.com/terraform-google-modules/terraform-google-kubernetes-engine/tree/master/modules/workload-identity

Detailed design

No response

Additional information

No response