[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/scheduling/v1beta1/types.go b/vendor/k8s.io/api/scheduling/v1beta1/types.go
index a9aaa86..f806ecd 100644
--- a/vendor/k8s.io/api/scheduling/v1beta1/types.go
+++ b/vendor/k8s.io/api/scheduling/v1beta1/types.go
@@ -17,6 +17,7 @@
 package v1beta1
 
 import (
+	apiv1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 )
 
@@ -24,12 +25,13 @@
 // +genclient:nonNamespaced
 // +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object
 
+// DEPRECATED - This group version of PriorityClass is deprecated by scheduling.k8s.io/v1/PriorityClass.
 // PriorityClass defines mapping from a priority class name to the priority
 // integer value. The value can be any valid integer.
 type PriorityClass struct {
 	metav1.TypeMeta `json:",inline"`
 	// Standard object's metadata.
-	// More info: https://git.k8s.io/community/contributors/devel/api-conventions.md#metadata
+	// More info: https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#metadata
 	// +optional
 	metav1.ObjectMeta `json:"metadata,omitempty" protobuf:"bytes,1,opt,name=metadata"`
 
@@ -49,6 +51,13 @@
 	// when this priority class should be used.
 	// +optional
 	Description string `json:"description,omitempty" protobuf:"bytes,4,opt,name=description"`
+
+	// PreemptionPolicy is the Policy for preempting pods with lower priority.
+	// One of Never, PreemptLowerPriority.
+	// Defaults to PreemptLowerPriority if unset.
+	// This field is alpha-level and is only honored by servers that enable the NonPreemptingPriority feature.
+	// +optional
+	PreemptionPolicy *apiv1.PreemptionPolicy `json:"preemptionPolicy,omitempty" protobuf:"bytes,5,opt,name=preemptionPolicy"`
 }
 
 // +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object
@@ -57,7 +66,7 @@
 type PriorityClassList struct {
 	metav1.TypeMeta `json:",inline"`
 	// Standard list metadata
-	// More info: https://git.k8s.io/community/contributors/devel/api-conventions.md#metadata
+	// More info: https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#metadata
 	// +optional
 	metav1.ListMeta `json:"metadata,omitempty" protobuf:"bytes,1,opt,name=metadata"`