Update the API reference for the update container

After this patch [0] we can update the container information
to rename also using [1], But API reference is still belongs
to the old rename container API[2] which should be updated.

[0] https://review.openstack.org/#/c/557595/
[1] https://developer.openstack.org/api-ref/application-container/#update-information-of-container
[2] https://developer.openstack.org/api-ref/application-container/#rename-a-container

Change-Id: I311e27241a380f24532bccc748b40b8594847833
Closes-Bug: #1762300

api-ref/source/containers.inc

@@ -350,7 +350,7 @@ Update information of container
 
 .. rest_method:: PATCH /v1/containers/{container_ident}
 
-Update information of one container attributes. Currently only `cpu` and
+Update information of one container attributes. Currently only `cpu`, name and
 `memory` can be updated.
 
 Response Codes
@@ -375,6 +375,7 @@ Request
   - container_ident: container_ident
   - memory: memory
   - cpu: cpu
+  - name: name
 
 Request Example
 ----------------

api-ref/source/samples/container-update-req.json

@@ -1,4 +1,5 @@
 {
     "memory": "200",
-    "cpu": "3"
+    "cpu": "3",
+    "name": "test_new"
 }

api-ref/source/samples/container-update-resp.json

@@ -40,7 +40,7 @@
     "image_driver": "docker",
     "task_state": null,
     "status_reason": null,
-    "name": "test",
+    "name": "test_new",
     "restart_policy": {
         "MaximumRetryCount": "0",
         "Name": "no"