Update README with v3 release announcement

Announce upcoming release of v3 with project rename and repository move.

Author: crazywhalecc

README.md

@@ -1,5 +1,11 @@
 # static-php-cli
 
+> [!IMPORTANT]
+> We are preparing to release **v3**, which will include a project rename from **static-php-cli** to **StaticPHP**.
+> The repository will also be moved to **static-php/static-php**.
+> Please update your references and stay tuned for the official release.
+
+
 [![Chinese readme](https://img.shields.io/badge/README-%E4%B8%AD%E6%96%87%20%F0%9F%87%A8%F0%9F%87%B3-moccasin?style=flat-square)](README-zh.md)
 [![English readme](https://img.shields.io/badge/README-English%20%F0%9F%87%AC%F0%9F%87%A7-moccasin?style=flat-square)](README.md)
 [![Releases](https://img.shields.io/packagist/v/crazywhalecc/static-php-cli?include_prereleases&label=Release&style=flat-square)](https://github.com/crazywhalecc/static-php-cli/releases)