Migrate from dep to go module

Signed-off-by: Madhu Rajanna <madhupr007@gmail.com>

vendor/go.etcd.io/etcd/clientv3/README.md

@@ -0,0 +1,85 @@
+# etcd/clientv3
+
+[![Docs](https://img.shields.io/badge/docs-latest-green.svg)](https://etcd.io/docs)
+[![Godoc](https://img.shields.io/badge/go-documentation-blue.svg?style=flat-square)](https://godoc.org/go.etcd.io/etcd/clientv3)
+
+`etcd/clientv3` is the official Go etcd client for v3.
+
+## Install
+
+```bash
+go get go.etcd.io/etcd/clientv3
+```
+
+## Get started
+
+Create client using `clientv3.New`:
+
+```go
+cli, err := clientv3.New(clientv3.Config{
+	Endpoints:   []string{"localhost:2379", "localhost:22379", "localhost:32379"},
+	DialTimeout: 5 * time.Second,
+})
+if err != nil {
+	// handle error!
+}
+defer cli.Close()
+```
+
+etcd v3 uses [`gRPC`](https://www.grpc.io) for remote procedure calls. And `clientv3` uses
+[`grpc-go`](https://github.com/grpc/grpc-go) to connect to etcd. Make sure to close the client after using it.
+If the client is not closed, the connection will have leaky goroutines. To specify client request timeout,
+pass `context.WithTimeout` to APIs:
+
+```go
+ctx, cancel := context.WithTimeout(context.Background(), timeout)
+resp, err := cli.Put(ctx, "sample_key", "sample_value")
+cancel()
+if err != nil {
+    // handle error!
+}
+// use the response
+```
+
+For full compatibility, it is recommended to vendor builds using etcd's vendored packages, using tools like `golang/dep`, as in [vendor directories](https://golang.org/cmd/go/#hdr-Vendor_Directories).
+
+## Error Handling
+
+etcd client returns 2 types of errors:
+
+1. context error: canceled or deadline exceeded.
+2. gRPC error: see [api/v3rpc/rpctypes](https://godoc.org/go.etcd.io/etcd/etcdserver/api/v3rpc/rpctypes).
+
+Here is the example code to handle client errors:
+
+```go
+resp, err := cli.Put(ctx, "", "")
+if err != nil {
+	switch err {
+	case context.Canceled:
+		log.Fatalf("ctx is canceled by another routine: %v", err)
+	case context.DeadlineExceeded:
+		log.Fatalf("ctx is attached with a deadline is exceeded: %v", err)
+	case rpctypes.ErrEmptyKey:
+		log.Fatalf("client-side error: %v", err)
+	default:
+		log.Fatalf("bad cluster endpoints, which are not etcd servers: %v", err)
+	}
+}
+```
+
+## Metrics
+
+The etcd client optionally exposes RPC metrics through [go-grpc-prometheus](https://github.com/grpc-ecosystem/go-grpc-prometheus). See the [examples](https://github.com/etcd-io/etcd/blob/master/clientv3/example_metrics_test.go).
+
+## Namespacing
+
+The [namespace](https://godoc.org/go.etcd.io/etcd/clientv3/namespace) package provides `clientv3` interface wrappers to transparently isolate client requests to a user-defined prefix.
+
+## Request size limit
+
+Client request size limit is configurable via `clientv3.Config.MaxCallSendMsgSize` and `MaxCallRecvMsgSize` in bytes. If none given, client request send limit defaults to 2 MiB including gRPC overhead bytes. And receive limit defaults to `math.MaxInt32`.
+
+## Examples
+
+More code examples can be found at [GoDoc](https://godoc.org/go.etcd.io/etcd/clientv3).