[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/client-go/kubernetes/scheme/register.go b/vendor/k8s.io/client-go/kubernetes/scheme/register.go
index e336eb9..8346d26 100644
--- a/vendor/k8s.io/client-go/kubernetes/scheme/register.go
+++ b/vendor/k8s.io/client-go/kubernetes/scheme/register.go
@@ -19,7 +19,6 @@
 package scheme
 
 import (
-	admissionregistrationv1alpha1 "k8s.io/api/admissionregistration/v1alpha1"
 	admissionregistrationv1beta1 "k8s.io/api/admissionregistration/v1beta1"
 	appsv1 "k8s.io/api/apps/v1"
 	appsv1beta1 "k8s.io/api/apps/v1beta1"
@@ -36,15 +35,20 @@
 	batchv1beta1 "k8s.io/api/batch/v1beta1"
 	batchv2alpha1 "k8s.io/api/batch/v2alpha1"
 	certificatesv1beta1 "k8s.io/api/certificates/v1beta1"
+	coordinationv1 "k8s.io/api/coordination/v1"
 	coordinationv1beta1 "k8s.io/api/coordination/v1beta1"
 	corev1 "k8s.io/api/core/v1"
 	eventsv1beta1 "k8s.io/api/events/v1beta1"
 	extensionsv1beta1 "k8s.io/api/extensions/v1beta1"
 	networkingv1 "k8s.io/api/networking/v1"
+	networkingv1beta1 "k8s.io/api/networking/v1beta1"
+	nodev1alpha1 "k8s.io/api/node/v1alpha1"
+	nodev1beta1 "k8s.io/api/node/v1beta1"
 	policyv1beta1 "k8s.io/api/policy/v1beta1"
 	rbacv1 "k8s.io/api/rbac/v1"
 	rbacv1alpha1 "k8s.io/api/rbac/v1alpha1"
 	rbacv1beta1 "k8s.io/api/rbac/v1beta1"
+	schedulingv1 "k8s.io/api/scheduling/v1"
 	schedulingv1alpha1 "k8s.io/api/scheduling/v1alpha1"
 	schedulingv1beta1 "k8s.io/api/scheduling/v1beta1"
 	settingsv1alpha1 "k8s.io/api/settings/v1alpha1"
@@ -62,11 +66,10 @@
 var Codecs = serializer.NewCodecFactory(Scheme)
 var ParameterCodec = runtime.NewParameterCodec(Scheme)
 var localSchemeBuilder = runtime.SchemeBuilder{
-	admissionregistrationv1alpha1.AddToScheme,
 	admissionregistrationv1beta1.AddToScheme,
+	appsv1.AddToScheme,
 	appsv1beta1.AddToScheme,
 	appsv1beta2.AddToScheme,
-	appsv1.AddToScheme,
 	auditregistrationv1alpha1.AddToScheme,
 	authenticationv1.AddToScheme,
 	authenticationv1beta1.AddToScheme,
@@ -80,16 +83,21 @@
 	batchv2alpha1.AddToScheme,
 	certificatesv1beta1.AddToScheme,
 	coordinationv1beta1.AddToScheme,
+	coordinationv1.AddToScheme,
 	corev1.AddToScheme,
 	eventsv1beta1.AddToScheme,
 	extensionsv1beta1.AddToScheme,
 	networkingv1.AddToScheme,
+	networkingv1beta1.AddToScheme,
+	nodev1alpha1.AddToScheme,
+	nodev1beta1.AddToScheme,
 	policyv1beta1.AddToScheme,
 	rbacv1.AddToScheme,
 	rbacv1beta1.AddToScheme,
 	rbacv1alpha1.AddToScheme,
 	schedulingv1alpha1.AddToScheme,
 	schedulingv1beta1.AddToScheme,
+	schedulingv1.AddToScheme,
 	settingsv1alpha1.AddToScheme,
 	storagev1beta1.AddToScheme,
 	storagev1.AddToScheme,