build: move e2e dependencies into e2e/go.mod

Several packages are only used while running the e2e suite. These
packages are less important to update, as the they can not influence the
final executable that is part of the Ceph-CSI container-image.

By moving these dependencies out of the main Ceph-CSI go.mod, it is
easier to identify if a reported CVE affects Ceph-CSI, or only the
testing (like most of the Kubernetes CVEs).

Signed-off-by: Niels de Vos <ndevos@ibm.com>

e2e/vendor/go.etcd.io/etcd/client/v3/README.md

@@ -0,0 +1,92 @@
+# 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/client/v3
+```
+
+Warning: As etcd 3.5.0 was not yet released, the command above does not work. 
+After first pre-release of 3.5.0 [#12498](https://github.com/etcd-io/etcd/issues/12498), 
+etcd can be referenced using: 
+```
+go get go.etcd.io/etcd/client/v3@v3.5.0-pre
+```
+
+## 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 install released versions of clients using go modules.
+
+## 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/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/main/tests/integration/clientv3/examples/example_metrics_test.go).
+
+## Namespacing
+
+The [namespace](https://godoc.org/go.etcd.io/etcd/client/v3/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](https://github.com/etcd-io/etcd/tree/main/tests/integration/clientv3/examples) can be found at [GoDoc](https://pkg.go.dev/go.etcd.io/etcd/client/v3).