Update Discord and Contributing Guide URLs (#9270)

Signed-off-by: Glenn Jocher <glenn.jocher@ultralytics.com>

docs/en/yolov5/index.md

@@ -88,6 +88,6 @@ This badge indicates that all [YOLOv5 GitHub Actions](https://github.com/ultraly
 
 Your journey with YOLOv5 doesn't have to be a solitary one. Join our vibrant community on [GitHub](https://github.com/ultralytics/yolov5), connect with professionals on [LinkedIn](https://www.linkedin.com/company/ultralytics/), share your results on [Twitter](https://twitter.com/ultralytics), and find educational resources on [YouTube](https://youtube.com/ultralytics). Follow us on [TikTok](https://www.tiktok.com/@ultralytics) and [Instagram](https://www.instagram.com/ultralytics/) for more engaging content.
 
-Interested in contributing? We welcome contributions of all forms; from code improvements and bug reports to documentation updates. Check out our [contributing guidelines](https://github.com/ultralytics/yolov5/blob/master/CONTRIBUTING.md) for more information.
+Interested in contributing? We welcome contributions of all forms; from code improvements and bug reports to documentation updates. Check out our [contributing guidelines](https://docs.ultralytics.com/help/contributing/) for more information.
 
 We're excited to see the innovative ways you'll use YOLOv5. Dive in, experiment, and revolutionize your computer vision projects! 🚀

examples/heatmaps.ipynb

@@ -130,7 +130,7 @@
         "- About Us – https://ultralytics.com/about\n",
         "- Join Our Team – https://ultralytics.com/work\n",
         "- Contact Us – https://ultralytics.com/contact\n",
-        "- Discord – https://discord.gg/2wNGbc6g9X\n",
+        "- Discord – https://ultralytics.com/discord\n",
         "- Ultralytics License – https://ultralytics.com/license\n",
         "\n",
         "YOLOv8 🚀 resources\n",

examples/object_counting.ipynb

@@ -132,7 +132,7 @@
         "- About Us – https://ultralytics.com/about\n",
         "- Join Our Team – https://ultralytics.com/work\n",
         "- Contact Us – https://ultralytics.com/contact\n",
-        "- Discord – https://discord.gg/2wNGbc6g9X\n",
+        "- Discord – https://ultralytics.com/discord\n",
         "- Ultralytics License – https://ultralytics.com/license\n",
         "\n",
         "YOLOv8 🚀 resources\n",

examples/object_tracking.ipynb

@@ -188,7 +188,7 @@
         "- About Us – https://ultralytics.com/about\n",
         "- Join Our Team – https://ultralytics.com/work\n",
         "- Contact Us – https://ultralytics.com/contact\n",
-        "- Discord – https://discord.gg/2wNGbc6g9X\n",
+        "- Discord – https://ultralytics.com/discord\n",
         "- Ultralytics License – https://ultralytics.com/license\n",
         "\n",
         "YOLOv8 🚀 resources\n",