[v2] aws2 eks update-kubeconfig should use current binary name

Issue reported originally here: https://github.com/weaveworks/eksctl/issues/1562
Related issue(resolved): https://github.com/kubernetes-sigs/aws-iam-authenticator/issues/132

Fixed this in the same way #132 was fixed by editing the kube config file.

`$ vim "/Users/home_dir/.kube/config"`

user:
exec:
apiVersion: client.authentication.k8s.io/v1alpha1
args:
- --region
- xxxxxregion_namexxxxx
- eks
- get-token
- --cluster-name
- xxxxxxxxxxxxcluster_idxxxxx
command: aws

In this instance, I changed the **command** field to: **`aws2`**

And now I'm able to run:
` $ eksctl get clusters`
`$ kubectl get svc --all-namespaces`