[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/apimachinery/pkg/apis/meta/v1/meta.go b/vendor/k8s.io/apimachinery/pkg/apis/meta/v1/meta.go
index 05f07ad..37141bd 100644
--- a/vendor/k8s.io/apimachinery/pkg/apis/meta/v1/meta.go
+++ b/vendor/k8s.io/apimachinery/pkg/apis/meta/v1/meta.go
@@ -94,6 +94,8 @@
 	SetSelfLink(selfLink string)
 	GetContinue() string
 	SetContinue(c string)
+	GetRemainingItemCount() *int64
+	SetRemainingItemCount(c *int64)
 }
 
 // Type exposes the type and APIVersion of versioned or internal API objects.
@@ -105,12 +107,16 @@
 	SetKind(kind string)
 }
 
+var _ ListInterface = &ListMeta{}
+
 func (meta *ListMeta) GetResourceVersion() string        { return meta.ResourceVersion }
 func (meta *ListMeta) SetResourceVersion(version string) { meta.ResourceVersion = version }
 func (meta *ListMeta) GetSelfLink() string               { return meta.SelfLink }
 func (meta *ListMeta) SetSelfLink(selfLink string)       { meta.SelfLink = selfLink }
 func (meta *ListMeta) GetContinue() string               { return meta.Continue }
 func (meta *ListMeta) SetContinue(c string)              { meta.Continue = c }
+func (meta *ListMeta) GetRemainingItemCount() *int64     { return meta.RemainingItemCount }
+func (meta *ListMeta) SetRemainingItemCount(c *int64)    { meta.RemainingItemCount = c }
 
 func (obj *TypeMeta) GetObjectKind() schema.ObjectKind { return obj }