AWS Load Balancer Operator support AWS GovCloud

1. Proposed title of this feature request
AWS Load Balancer Operator (ALBO) support AWS GovCloud

2. What is the nature and description of the request?
Now ALBO already can work on normal AWS region, but the test failed on AWS Gov region.

3. Why does the customer need this? (List the business requirements here)
Customers may need this

4. List any affected packages or components.
ALB operator and controller

e.g. https://github.com/kubernetes-sigs/aws-load-balancer-controller/blob/main/docs/install/iam_policy_us-gov.json