update milestone doc

doc/guide/milestone.md

@@ -1,7 +1,3 @@
-## 2023-06-10
-
-文档与示例站点拆分打包，加快首次加载速度。
-
 ## 2023-05-03
 
 将组件源码与文档分开，避免 node_modules 体积过大。

doc/guide/milestone_en.md

@@ -1,7 +1,3 @@
-## 2023-06-10
-
-Splitting and packaging documents and sample sites to speed up the initial loading speed.
-
 ## 2023-05-03
 
 Separate component source code and documentation to avoid large node_modules size.