Update README.md

Author: tezpark

ios/README.md

@@ -23,7 +23,7 @@ The **Sendbird AI Agent Messenger** allows seamless integration of chatbot featu
 
 The minimum requirements for AI Agent for iOS are the following.
 
-- Xcode 15.0 or later
+- Xcode 16.0 or later
 - Swift Package Manager (SPM) support
 
 ## Prerequisites