add: add role's custom config

metagpt/configs/role_custom_config.py

@@ -0,0 +1,19 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+"""
+@Time    : 2024/4/22 16:33
+@Author  : Justin
+@File    : role_custom_config.py
+"""
+from metagpt.configs.llm_config import LLMConfig
+from metagpt.utils.yaml_model import YamlModel
+
+
+class RoleCustomConfig(YamlModel):
+    """custom config for roles
+    role: role's className or role's role_id
+    To be expanded
+    """
+    role: str = ""
+    llm: LLMConfig
+