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/adapters/common/request_handler.go b/pkg/adapters/common/request_handler.go
index f3a93df..50b9195 100644
--- a/pkg/adapters/common/request_handler.go
+++ b/pkg/adapters/common/request_handler.go
@@ -21,13 +21,13 @@
 
 	"github.com/golang/protobuf/ptypes"
 	"github.com/golang/protobuf/ptypes/empty"
-	"github.com/opencord/voltha-lib-go/v3/pkg/adapters"
-	"github.com/opencord/voltha-lib-go/v3/pkg/adapters/adapterif"
-	"github.com/opencord/voltha-lib-go/v3/pkg/kafka"
-	"github.com/opencord/voltha-lib-go/v3/pkg/log"
-	ic "github.com/opencord/voltha-protos/v3/go/inter_container"
-	"github.com/opencord/voltha-protos/v3/go/openflow_13"
-	"github.com/opencord/voltha-protos/v3/go/voltha"
+	"github.com/opencord/voltha-lib-go/v4/pkg/adapters"
+	"github.com/opencord/voltha-lib-go/v4/pkg/adapters/adapterif"
+	"github.com/opencord/voltha-lib-go/v4/pkg/kafka"
+	"github.com/opencord/voltha-lib-go/v4/pkg/log"
+	ic "github.com/opencord/voltha-protos/v4/go/inter_container"
+	"github.com/opencord/voltha-protos/v4/go/openflow_13"
+	"github.com/opencord/voltha-protos/v4/go/voltha"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/status"
 )