doc[upgrade]: upgrade doc

README.md

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 English | [简体中文](./README_CN.md)
 <a href="https://github.com/zfoo-project/zfoo"><img src="/doc/image/logo.jpg" width="30%"></a>
 
+-----------
+Attention:
+-----------
+
+- The main branch is a development version for Java 21 and GraalVM. The stable version is [zfoo-java-11-17](https://github.com/zfoo-project/zfoo/tree/zfoo-java-11-17)
+- Upgrade process
+  - reimport not found classes
+  - no need to inherit IPacket anymore
+  - SafeRunnable has been deleted, please use ThreadUtils.safeRunnable()
+  - rename interfaces and annotations，Storage -> IStorage，@Resource -> @Storage，@ResInjection -> @StorageAutowired
+  - rename interfaces and annotations，@EntityCachesInjection -> @EntityCacheAutowired，@EntityCaches -> @EntityCache
+
+
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 Why is zfoo protocol ?
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