update install command

Author: AmberC0209

docs/paddlex/quick_start.en.md

@@ -24,7 +24,7 @@ python -m pip install paddlepaddle-gpu==3.0.0b1 -i https://www.paddlepaddle.org.
 * **Installing PaddleX**
 
 ```bash
-pip install https://paddle-model-ecology.bj.bcebos.com/paddlex/whl/paddlex-3.0.0b1-py3-none-any.whl
+pip install paddlex==3.0.0b2
 ```
 
 > ❗For more installation methods, refer to the [PaddleX Installation Guide](https://github.com/PaddlePaddle/PaddleX/blob/release/3.0-beta1/docs/installation/installation_en.md).

docs/paddlex/quick_start.md

@@ -27,7 +27,7 @@ python -m pip install paddlepaddle-gpu==3.0.0b2 -i https://www.paddlepaddle.org.
 * **安装PaddleX**
 
 ```bash
-pip install https://paddle-model-ecology.bj.bcebos.com/paddlex/whl/paddlex-3.0.0b2-py3-none-any.whl
+pip install paddlex==3.0.0b2
 ```
 
 > ❗ 更多安装方式参考[PaddleX安装教程](https://paddlepaddle.github.io/PaddleX/latest/installation/installation.html)