Update README.md (#5686)

Author: c121914yu

README.md

@@ -106,7 +106,7 @@ https://github.com/labring/FastGPT/assets/15308462/7d3a38df-eb0e-4388-9250-2409b
 * [部署 FastGPT](https://doc.fastgpt.io/docs/introduction/development/sealos/)
 * [系统配置文件说明](https://doc.fastgpt.io/docs/introduction/development/configuration/)
 * [多模型配置方案](https://doc.fastgpt.io/docs/introduction/development/modelConfig/one-api/)
-* [版本更新/升级介绍](https://doc.fastgpt.io/docs/introduction/development/upgrading/index)
+* [版本更新/升级介绍](https://doc.fastgpt.io/docs/upgrading)
 * [OpenAPI API 文档](https://doc.fastgpt.io/docs/introduction/development/openapi/)
 * [知识库结构详解](https://doc.fastgpt.io/docs/introduction/guide/knowledge_base/RAG/)