test/unit, update admissionregistration to v1 in merge_test.go
@@ -292,7 +292,7 @@ metadata:
}
var (
template = `
-apiVersion: admissionregistration.k8s.io/v1beta1
+apiVersion: admissionregistration.k8s.io/v1
kind: MutatingWebhookConfiguration
metadata:
name: nmstate
