Update README.md including the announcement blog post (#9)

Author: babaknasri

README.md

@@ -22,7 +22,7 @@ The Code Review extension adds the `/code-review` command to Gemini CLI which an
 ## Resources
 
 - [Gemini CLI extensions](https://github.com/google-gemini/gemini-cli/blob/main/docs/extensions/index.md): Documentation about using extensions in Gemini CLI
-- Blog post (coming soon!): More information about the Code Review extension
+- [Blog post](https://blog.google/technology/developers/gemini-cli-extensions/): Announcement of Gemini CLI Extensions
 - [GitHub issues](https://github.com/gemini-cli-extensions/code-review/issues): Report bugs or request features
 
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