update doc link (#2664)

fluid/PaddleCV/object_detection/README.md

@@ -3,4 +3,4 @@ Hi!
 
 This directory has been deprecated.
 
-Please visit the project at [PaddleCV/object_detection](../../../PaddleCV/object_detection).
+Please visit the project at [PaddleCV/PaddleDetection](../../../PaddleCV/PaddleDetection).

fluid/PaddleCV/object_detection/README_cn.md

 
-您好，该项目已被迁移，请移步到 [PaddleCV/object_detection](../../../PaddleCV/object_detection) 目录下浏览本项目。
+您好，该项目已被迁移，请移步到 [PaddleCV/PaddleDetection](../../../PaddleCV/PaddleDetection) 目录下浏览本项目。

fluid/PaddleCV/object_detection/README_quant.md

@@ -3,4 +3,4 @@ Hi!
 
 This directory has been deprecated.
 
-Please visit the project at [PaddleCV/object_detection](../../../PaddleCV/object_detection).
+Please visit the project at [PaddleCV/ssd](../../../PaddleCV/ssd).

fluid/PaddleCV/rcnn/README.md

@@ -3,4 +3,4 @@ Hi!
 
 This directory has been deprecated.
 
-Please visit the project at [PaddleCV/rcnn](../../../PaddleCV/rcnn).
+Please visit the project at [PaddleCV/PaddleDetection](../../../PaddleCV/PaddleDetection).

fluid/PaddleCV/rcnn/README_cn.md

 
-您好，该项目已被迁移，请移步到 [PaddleCV/rcnn](../../../PaddleCV/rcnn) 目录下浏览本项目。
+您好，该项目已被迁移，请移步到 [PaddleCV/PaddleDetection](../../../PaddleCV/PaddleDetection) 目录下浏览本项目。

fluid/PaddleCV/yolov3/README.md

@@ -3,4 +3,4 @@ Hi!
 
 This directory has been deprecated.
 
-Please visit the project at [PaddleCV/yolov3](../../../PaddleCV/yolov3).
+Please visit the project at [PaddleCV/PaddleDetection](../../../PaddleCV/PaddleDetection).

fluid/PaddleCV/yolov3/README_cn.md

 
-您好，该项目已被迁移，请移步到 [PaddleCV/yolov3](../../../PaddleCV/yolov3) 目录下浏览本项目。
+您好，该项目已被迁移，请移步到 [PaddleCV/PaddleDetection](../../../PaddleCV/PaddleDetection) 目录下浏览本项目。