Moving all references to proto v4

Change-Id: Idbb9119da7ddae136f7ffbbb783429c7e049b3ab
diff --git a/protos/voltha_protos/ponsim.proto b/protos/voltha_protos/ponsim.proto
index 202ccdb..ebfefc3 100644
--- a/protos/voltha_protos/ponsim.proto
+++ b/protos/voltha_protos/ponsim.proto
@@ -1,6 +1,6 @@
 syntax = "proto3";
 
-option go_package = "github.com/opencord/voltha-protos/v3/go/voltha";
+option go_package = "github.com/opencord/voltha-protos/v4/go/voltha";
 option java_package = "org.opencord.voltha";
 
 package voltha;