VOL-1643 Update voltha-lib-go to use voltha-protos v3.0.0

and bump up the version to 3.0.0. voltha-protos is modified to be
compatible with the java language proto compilation. It's a major
change and a major version change has been made.

Change-Id: Ifb93430567ddf96aaa0fbf6e5853aad9e1070f6f
diff --git a/pkg/flows/flow_utils_test.go b/pkg/flows/flow_utils_test.go
index a9dc9cc..fc2ff27 100644
--- a/pkg/flows/flow_utils_test.go
+++ b/pkg/flows/flow_utils_test.go
@@ -17,12 +17,13 @@
 
 import (
 	"bytes"
-	ofp "github.com/opencord/voltha-protos/v2/go/openflow_13"
+	"strings"
+	"testing"
+
+	ofp "github.com/opencord/voltha-protos/v3/go/openflow_13"
 	"github.com/stretchr/testify/assert"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/status"
-	"strings"
-	"testing"
 )
 
 var (