Bump google.golang.org/grpc from 1.38.0 to 1.53.0

Bumps [google.golang.org/grpc](https://github.com/grpc/grpc-go) from 1.38.0 to 1.53.0.
- [Release notes](https://github.com/grpc/grpc-go/releases)
- [Commits](grpc/grpc-go@v1.38.0...v1.53.0)

---
updated-dependencies:
- dependency-name: google.golang.org/grpc
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

go.mod

@@ -13,10 +13,9 @@ require (
 	github.com/zhaohuabing/debounce v1.0.0
 	go.etcd.io/etcd/api/v3 v3.5.0
 	go.etcd.io/etcd/client/v3 v3.5.0
-	golang.org/x/net v0.0.0-20210805182204-aaa1db679c0d
-	golang.org/x/sync v0.0.0-20210220032951-036812b2e83c
-	golang.org/x/tools v0.1.7 // indirect
-	google.golang.org/grpc v1.38.0
+	golang.org/x/net v0.5.0
+	golang.org/x/sync v0.1.0
+	google.golang.org/grpc v1.53.0
 	istio.io/api v0.0.0-20210601145914-9a4239731e79
 	istio.io/client-go v0.0.0-20210601151459-89ee09f12704
 	istio.io/istio v0.0.0-20210603041206-aa439f6e4772