Fix subflow type annotation, which was wrong (#173)

it wasn't caught in older versions of pydantic because (I think)
the Self keyword was not supported yet.

src/schemas/flows.py

@@ -1,5 +1,7 @@
+from __future__ import annotations
+
 from datetime import datetime
-from typing import Any, Self
+from typing import Any, TypedDict
 
 from pydantic import BaseModel, ConfigDict, Field
 
@@ -23,7 +25,12 @@ class Flow(BaseModel):
  language: str | None = Field(max_length=128)
  dependencies: str | None
  parameter: list[Parameter]
- subflows: list[Self]
+ subflows: list[Subflow]
  tag: list[str]
 
  model_config = ConfigDict(arbitrary_types_allowed=True)
+
+
+class Subflow(TypedDict):
+ identifier: str | None
+ flow: Flow