fix: default model value in config (#256)

* fix: git default model value

* Update README.md

Author: you-n-g

README.md

@@ -8,7 +8,6 @@
 [![CodeQL](https://github.com/microsoft/RD-Agent/actions/workflows/github-code-scanning/codeql/badge.svg)](https://github.com/microsoft/RD-Agent/actions/workflows/github-code-scanning/codeql)
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@@ -18,6 +17,7 @@
 [![pre-commit](https://img.shields.io/badge/pre--commit-enabled-brightgreen?logo=pre-commit)](https://github.com/pre-commit/pre-commit)
 [![Checked with mypy](https://www.mypy-lang.org/static/mypy_badge.svg)](http://mypy-lang.org/)
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+[![Readthedocs Preview](https://github.com/microsoft/RD-Agent/actions/workflows/readthedocs-preview.yml/badge.svg)](https://github.com/microsoft/RD-Agent/actions/workflows/readthedocs-preview.yml) <!-- this badge is too long, please place it in the last one to make it pretty --> 
 
 # 📰 News
 | 🗞️ News        | 📝 Description                 |

rdagent/core/conf.py

@@ -38,7 +38,7 @@ class RDAgentSettings(BaseSettings):
     chat_openai_api_key: str = ""
     chat_azure_api_base: str = ""
     chat_azure_api_version: str = ""
-    chat_model: str = ""
+    chat_model: str = "gpt-4-turbo"
     chat_max_tokens: int = 3000
     chat_temperature: float = 0.5
     chat_stream: bool = True