VOL-1596 Add Support for handling multicast groups in OpenOLT Adapter.
VOL-1595 Add Support for handling multicast flows in OpenOLT Adapter.

Depends voltha-protos from the patch below:
https://gerrit.opencord.org/#/c/16690/

Change-Id: I1cc9900bd6400bb31aed11beda674138838a21d2
diff --git a/mocks/mockOpenOltClient.go b/mocks/mockOpenOltClient.go
index 00a9fd5..652f959 100644
--- a/mocks/mockOpenOltClient.go
+++ b/mocks/mockOpenOltClient.go
@@ -22,8 +22,8 @@
 	"errors"
 	"io"
 
-	openolt "github.com/opencord/voltha-protos/v2/go/openolt"
-	tech_profile "github.com/opencord/voltha-protos/v2/go/tech_profile"
+	openolt "github.com/opencord/voltha-protos/v3/go/openolt"
+	tech_profile "github.com/opencord/voltha-protos/v3/go/tech_profile"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/metadata"
 )
@@ -222,3 +222,8 @@
 func (mock *mockOpenoltEnableIndicationClient) RecvMsg(m interface{}) error {
 	return nil
 }
+
+// PerformGroupOperation mocks the PerformGroupOperation function of Openoltclient.
+func (ooc *MockOpenoltClient) PerformGroupOperation(ctx context.Context, in *openolt.Group, opts ...grpc.CallOption) (*openolt.Empty, error) {
+	return &openolt.Empty{}, nil
+}