docs: Fix typo in README.md (#95)

Author: camus-cheung-fit2cloud

README.md

@@ -51,7 +51,7 @@ docker run -d --name=maxkb -p 8080:8080 -v ~/.maxkb:/var/lib/postgresql/data 1pa
 
 -   前端：[Vue.js](https://cn.vuejs.org/)
 -   后端：[Python / Django](https://www.djangoproject.com/)
--   Langchain：[Langchain](https://www.langchain.com/)
+-   LangChain：[LangChain](https://www.langchain.com/)
 -   向量数据库：[PostgreSQL / pgvector](https://www.postgresql.org/)
 -   大模型：Azure OpenAI、百度千帆大模型、[Ollama](https://github.com/ollama/ollama)