[schema][algorithm][3] Add mandatory output to loop

beat/core/schema/algorithm/3.json

@@ -71,11 +71,13 @@
       "properties": {
         "name": { "type": "string" },
         "inputs": { "$ref": "common.json#/definitions/endpoints" },
+        "outputs": { "$ref": "common.json#/definitions/endpoints" },
         "loop": { "$ref": "#/definitions/loop_io_group" }
       },
 
       "required": [
         "inputs",
+        "outputs",
         "loop"
       ],