Add kind property (Azure#13279)

Author: srdan-bozovic-msft

specification/network/resource-manager/Microsoft.Network/stable/2020-11-01/serviceEndpointPolicy.json

@@ -712,6 +712,11 @@
           "readOnly": true,
           "type": "string",
           "description": "A unique read-only string that changes whenever the resource is updated."
+        },
+        "kind": {
+          "readOnly": true,
+          "type": "string",
+          "description": "Kind of service endpoint policy. This is metadata used for the Azure portal experience."
         }
       },
       "allOf": [