Fix competition link (ultralytics#3799)

* link to the competition repaired

* Update README.md

Co-authored-by: Glenn Jocher <glenn.jocher@ultralytics.com>

README.md

@@ -178,8 +178,10 @@ Get started in seconds with our verified environments and integrations, includin
 
 We are super excited about our first-ever Ultralytics YOLOv5 🚀 EXPORT Competition with **$10,000** in cash prizes!  
 
-<p align="center" href="https://github.com/ultralytics/yolov5/discussions/3213">
-  <img width="850" src="https://github.com/ultralytics/yolov5/releases/download/v1.0/banner-export-competition.png"></p>
+<p align="center">
+  <a href="https://github.com/ultralytics/yolov5/discussions/3213">
+  <img width="850" src="https://github.com/ultralytics/yolov5/releases/download/v1.0/banner-export-competition.png"></a>
+</p>
 
 
 ## <div align="center">Why YOLOv5</div>