move package to v2 version as per go requirements after update to version 2.0

Change-Id: Iac4cc56f014f49e7d241357f8b7a5f4f3047bedc
diff --git a/messagetypes.go b/messagetypes.go
index be5c37b..e139af7 100644
--- a/messagetypes.go
+++ b/messagetypes.go
@@ -18,7 +18,7 @@
 package omci
 
 import (
-	me "github.com/opencord/omci-lib-go/generated"
+	me "github.com/opencord/omci-lib-go/v2/generated"
 )
 
 // MessageType is the OMCI Message Type combined with the AR/AK flags as appropriate.