change version to 1.5 in yolov3 (#3619)

PaddleCV/yolov3/README.md

@@ -42,7 +42,7 @@
 
 **安装[PaddlePaddle](https://github.com/PaddlePaddle/Paddle)：**
 
-在当前目录下运行样例代码需要PadddlePaddle Fluid的v.1.4或以上的版本。如果你的运行环境中的PaddlePaddle低于此版本，请根据[安装文档](http://paddlepaddle.org/documentation/docs/zh/1.4/beginners_guide/install/index_cn.html)中的说明来更新PaddlePaddle。
+在当前目录下运行样例代码需要PadddlePaddle Fluid的v.1.5或以上的版本。如果你的运行环境中的PaddlePaddle低于此版本，请根据[安装文档](http://paddlepaddle.org/documentation/docs/zh/1.5/beginners_guide/install/index_cn.html)中的说明来更新PaddlePaddle。
 
 ### 数据准备
 

PaddleCV/yolov3/README_en.md

@@ -28,7 +28,7 @@ We also recommend users to take a look at the  [IPython Notebook demo](https:/
 
 **Install [PaddlePaddle](https://github.com/PaddlePaddle/Paddle):**
 
-Running sample code in this directory requires PaddelPaddle Fluid v.1.4 and later. If the PaddlePaddle on your device is lower than this version, please follow the instructions in [installation document](http://www.paddlepaddle.org/documentation/docs/en/1.4/beginners_guide/install/index_en.html) and make an update.
+Running sample code in this directory requires PaddelPaddle Fluid v.1.5 and later. If the PaddlePaddle on your device is lower than this version, please follow the instructions in [installation document](http://www.paddlepaddle.org/documentation/docs/en/1.5/beginners_guide/install/index_en.html) and make an update.
 
 **Install the [COCO-API](https://github.com/cocodataset/cocoapi):**