Add beta notice

Author: lgarber-akamai

linode_api4/groups/lke.py

@@ -104,6 +104,8 @@ def cluster_create(
         :param control_plane: The control plane configuration of this LKE cluster.
         :type control_plane: Dict[str, Any] or LKEClusterControlPlaneRequest
         :param apl_enabled: Whether this cluster should use APL.
+                            note:: This endpoint is in beta and may only
+                            function if base_url is set to `https://api.linode.com/v4beta`.
         :type apl_enabled: bool
         :param kwargs: Any other arguments to pass along to the API.  See the API
                        docs for possible values.