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

Change-Id: I32074b5c05b08f8ebd2205f8dc2af225bff465cc
diff --git a/rw_core/common.go b/rw_core/common.go
index d54fdde..ebefcc0 100644
--- a/rw_core/common.go
+++ b/rw_core/common.go
@@ -18,7 +18,7 @@
 package main
 
 import (
-	"github.com/opencord/voltha-lib-go/v3/pkg/log"
+	"github.com/opencord/voltha-lib-go/v4/pkg/log"
 )
 
 var logger log.CLogger