doc(php): fix install script

Author: ISAAC-XXYYZZ

README.md

@@ -55,7 +55,7 @@ npm install kucoin-universal-sdk
 ### PHP Installation(0.1.0-alpha)
 **Note**: This SDK is currently in the Alpha phase. We are actively iterating and improving its features, stability, and documentation. Feedback and contributions are highly encouraged to help us refine the SDK.
 ```bash
-composer require kucoin/kucoin-universal-sdk
+composer require kucoin/kucoin-universal-sdk=0.1.0-alpha
 ```
 
 ### Postman Installation  

sdk/php/README.md

@@ -20,7 +20,7 @@ For an overview of the project and SDKs in other languages, refer to the [Main R
 Install the SDK using `composer`:
 
 ```bash
-composer require kucoin/kucoin-universal-sdk
+composer require kucoin/kucoin-universal-sdk=0.1.0-alpha
 ```
 
 ## 📖 Getting Started