VOL-3589 Update voltha go to support new version v4 of voltha protos

Change-Id: I32074b5c05b08f8ebd2205f8dc2af225bff465cc
diff --git a/rw_core/core/api/common_test.go b/rw_core/core/api/common_test.go
index 92ba701..3a4fe8e 100644
--- a/rw_core/core/api/common_test.go
+++ b/rw_core/core/api/common_test.go
@@ -22,7 +22,7 @@
 
 	"github.com/golang/protobuf/ptypes/empty"
 	"github.com/google/uuid"
-	"github.com/opencord/voltha-protos/v3/go/voltha"
+	"github.com/opencord/voltha-protos/v4/go/voltha"
 	"google.golang.org/grpc/metadata"
 )