[aws] s3:HeadBucket permission does not exist

    The code requires the `s3:HeadObject` permission (https://github.com/openshift/cloud-credential-operator/blob/master/pkg/aws/utils.go#L57) but it doesn't exist. The AWS docs say the permission needed is `s3:ListBucket`: https://docs.aws.amazon.com/AmazonS3/latest/API/API_HeadBucket.html

    4.16

    always

    1. Try to install cluster with minimal permissions without s3:HeadBucket
    2.
    3.
    

level=warning msg=Action not allowed with tested creds action=iam:DeleteUserPolicy
level=warning msg=Tested creds not able to perform all requested actions
level=warning msg=Action not allowed with tested creds action=s3:HeadBucket
level=warning msg=Tested creds not able to perform all requested actions
level=fatal msg=failed to fetch Cluster: failed to fetch dependency of "Cluster": failed to generate asset "Platform Permissions Check": validate AWS credentials: AWS credentials cannot be used to either create new creds or use as-is
Installer exit with code 1

    Only `s3:ListBucket` should be checked.