[VOL-1866] Changed module dependency to v12.0.0 of k8s client-go and v1.15.4 of k8s api/apimachinery in sync with other voltha components

Had to use pseudo-version corresponding to v12.0.0 of k8s client-go
because golang proxy is no longer serving the modules not complying
to Semantic Import Versioning rules including client-go v12.0.0.
Refer to https://github.com/kubernetes/client-go/issues/631 and
https://github.com/golang/go/issues/33558

Change-Id: I2e558bab7f0702f230761319eb5392a7d0532ea3
diff --git a/vendor/k8s.io/api/apps/v1beta1/zz_generated.deepcopy.go b/vendor/k8s.io/api/apps/v1beta1/zz_generated.deepcopy.go
index 93892bf..fb27612 100644
--- a/vendor/k8s.io/api/apps/v1beta1/zz_generated.deepcopy.go
+++ b/vendor/k8s.io/api/apps/v1beta1/zz_generated.deepcopy.go
@@ -58,7 +58,7 @@
 func (in *ControllerRevisionList) DeepCopyInto(out *ControllerRevisionList) {
 	*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([]ControllerRevision, len(*in))
@@ -137,7 +137,7 @@
 func (in *DeploymentList) DeepCopyInto(out *DeploymentList) {
 	*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([]Deployment, len(*in))
@@ -470,7 +470,7 @@
 func (in *StatefulSetList) DeepCopyInto(out *StatefulSetList) {
 	*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([]StatefulSet, len(*in))