use istio client-go library instead of knative (#1661)

use istio client-go library instead of knative
bump kubernetes dependency version
change code coverage to codecov

vendor/k8s.io/api/auditregistration/v1alpha1/zz_generated.deepcopy.go

@@ -55,7 +55,7 @@ func (in *AuditSink) DeepCopyObject() runtime.Object {
 func (in *AuditSinkList) DeepCopyInto(out *AuditSinkList) {
 	*out = *in
 	out.TypeMeta = in.TypeMeta
-	out.ListMeta = in.ListMeta
+	in.ListMeta.DeepCopyInto(&out.ListMeta)
 	if in.Items != nil {
 		in, out := &in.Items, &out.Items
 		*out = make([]AuditSink, len(*in))
@@ -131,6 +131,11 @@ func (in *ServiceReference) DeepCopyInto(out *ServiceReference) {
 		*out = new(string)
 		**out = **in
 	}
+	if in.Port != nil {
+		in, out := &in.Port, &out.Port
+		*out = new(int32)
+		**out = **in
+	}
 	return
 }