deps: move from github.com/golang/protobuf to google.golang.org/protobuf/proto (#6919)

Co-authored-by: Arvind Bright <arvind.bright100@gmail.com>
Co-authored-by: Doug Fawley <dfawley@google.com>

Author: 3 people

balancer/grpclb/grpclb.go

@@ -44,8 +44,8 @@ import (
 	"google.golang.org/grpc/internal/resolver/dns"
 	"google.golang.org/grpc/resolver"
 	"google.golang.org/grpc/resolver/manual"
+	"google.golang.org/protobuf/types/known/durationpb"
 
-	durationpb "github.com/golang/protobuf/ptypes/duration"
 	lbpb "google.golang.org/grpc/balancer/grpclb/grpc_lb_v1"
 )
 

balancer/grpclb/grpclb_remote_balancer.go

@@ -26,7 +26,6 @@ import (
 	"sync"
 	"time"
 
-	"github.com/golang/protobuf/proto"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/balancer"
 	"google.golang.org/grpc/connectivity"
@@ -36,8 +35,9 @@ import (
 	"google.golang.org/grpc/keepalive"
 	"google.golang.org/grpc/metadata"
 	"google.golang.org/grpc/resolver"
+	"google.golang.org/protobuf/proto"
+	"google.golang.org/protobuf/types/known/timestamppb"
 
-	timestamppb "github.com/golang/protobuf/ptypes/timestamp"
 	lbpb "google.golang.org/grpc/balancer/grpclb/grpc_lb_v1"
 )