update whl recommend version

doc/doc_ch/whl.md

@@ -6,7 +6,7 @@
 
 pip安装
 ```bash
-pip install paddleocr
+pip install "paddleocr>=2.0.1" # 推荐使用2.0.1+版本
 ```
 
 本地构建并安装

doc/doc_en/whl_en.md

@@ -4,7 +4,7 @@
 ### install package
 install by pypi
 ```bash
-pip install paddleocr
+pip install "paddleocr>=2.0.1" # Recommend to use version 2.0.1+
 ```
 
 build own whl package and install