Add indentation to the cert parameters

Author: juampynr

content/en/docs/tasks/administer-cluster/configure-upgrade-etcd.md

@@ -130,10 +130,10 @@ communication:
 
 ```
 ETCDCTL_API=3 etcdctl --endpoints 10.2.0.9:2379 \
---cert=/etc/kubernetes/pki/etcd/server.crt \
---key=/etc/kubernetes/pki/etcd/server.key \
---cacert=/etc/kubernetes/pki/etcd/ca.crt \
-member list
+  --cert=/etc/kubernetes/pki/etcd/server.crt \
+  --key=/etc/kubernetes/pki/etcd/server.key \
+  --cacert=/etc/kubernetes/pki/etcd/ca.crt \
+  member list
 ```
 
 ### Limiting access of etcd clusters