fix: migrate to go.etcd.io import path (#9987)

with the merge of https://github.com/etcd-io/etcd/pull/11823
etcd v3.5.0 will now have a properly imported versioned path

this fixes our pending migration to newer repo

cmd/etcd.go

@@ -21,7 +21,7 @@ import (
 	"errors"
 	"fmt"
 
-	etcd "github.com/coreos/etcd/clientv3"
+	etcd "go.etcd.io/etcd/v3/clientv3"
 )
 
 var errEtcdUnreachable = errors.New("etcd is unreachable, please check your endpoints")