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/flows/flow_utils_test.go b/pkg/flows/flow_utils_test.go
index ec00cb1..20b7bbe 100644
--- a/pkg/flows/flow_utils_test.go
+++ b/pkg/flows/flow_utils_test.go
@@ -20,7 +20,7 @@
 	"strings"
 	"testing"
 
-	ofp "github.com/opencord/voltha-protos/v3/go/openflow_13"
+	ofp "github.com/opencord/voltha-protos/v4/go/openflow_13"
 	"github.com/stretchr/testify/assert"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/status"