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/db/backend.go b/pkg/db/backend.go
index b807253..23ad5a0 100644
--- a/pkg/db/backend.go
+++ b/pkg/db/backend.go
@@ -20,13 +20,14 @@
 	"context"
 	"errors"
 	"fmt"
-	"github.com/opencord/voltha-lib-go/v2/pkg/db/kvstore"
-	"github.com/opencord/voltha-lib-go/v2/pkg/log"
-	"google.golang.org/grpc/codes"
-	"google.golang.org/grpc/status"
 	"strconv"
 	"sync"
 	"time"
+
+	"github.com/opencord/voltha-lib-go/v3/pkg/db/kvstore"
+	"github.com/opencord/voltha-lib-go/v3/pkg/log"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
 )
 
 const (