admissionregistration.k8s.io/v1beta1 was deprecated in 1.22

[ss098]

What happened:

admissionregistration.k8s.io/v1beta1 api removed in kubernetes 1.22.

What you expected to happen:

https://github.com/aws/amazon-eks-pod-identity-webhook/blob/master/deploy/mutatingwebhook.yaml#L1

Migrate admissionregistration from v1beta1 to v1.

[h3poteto]

I think we need to merge #115 at first.

[LauraCameran]

I think this issue can be closed since commit d3d1b4c