Use voltha-protos version 4.0.2
Bump major version of voltha-lib-go to 4.0.0 as this change results
in incompatible API version compared to previous version

Change-Id: I1def58361fb1d85f07d6948ebf1ffb7a92eb0d4c
diff --git a/pkg/mocks/etcd/etcd_server_test.go b/pkg/mocks/etcd/etcd_server_test.go
index b26b262..0c2f882 100644
--- a/pkg/mocks/etcd/etcd_server_test.go
+++ b/pkg/mocks/etcd/etcd_server_test.go
@@ -19,8 +19,8 @@
 import (
 	"context"
 	"fmt"
-	"github.com/opencord/voltha-lib-go/v3/pkg/db/kvstore"
-	"github.com/opencord/voltha-lib-go/v3/pkg/log"
+	"github.com/opencord/voltha-lib-go/v4/pkg/db/kvstore"
+	"github.com/opencord/voltha-lib-go/v4/pkg/log"
 	"github.com/phayes/freeport"
 	"github.com/stretchr/testify/assert"
 	"os"