Add checkpoint subresource to Kublet authorization doc (#48012)

* Add checkpoint subresource to Kublet authorization doc

* Update kubelet-authn-authz.md

* Replace `spec` with `checkpoint` in subresource

content/en/docs/reference/access-authn-authz/kubelet-authn-authz.md

@@ -65,13 +65,14 @@ DELETE    | delete
 
 The resource and subresource is determined from the incoming request's path:
 
-Kubelet API  | resource | subresource
--------------|----------|------------
-/stats/\*     | nodes    | stats
-/metrics/\*   | nodes    | metrics
-/logs/\*      | nodes    | log
-/spec/\*      | nodes    | spec
-*all others* | nodes    | proxy
+Kubelet API         | resource | subresource
+--------------------|----------|------------
+/stats/\*           | nodes    | stats
+/metrics/\*         | nodes    | metrics
+/logs/\*            | nodes    | log
+/spec/\*            | nodes    | spec
+/checkpoint/\*      | nodes    | checkpoint
+*all others*        | nodes    | proxy
 
 The namespace and API group attributes are always an empty string, and
 the resource name is always the name of the kubelet's `Node` API object.