update readme with contributiong section (#298)

Co-authored-by: dylan <dylan@bitmind.ai>

Author: dylanuys

README.md

@@ -110,3 +110,7 @@ Validators are responsible for challenging and scoring both miner types. Generat
 </p> 
 
 [![Ask DeepWiki](https://deepwiki.com/badge.svg)](https://deepwiki.com/BitMind-AI/bitmind-subnet)
+
+## Contributing
+
+Contributions are welcome and can be made via a pull request to the `testnet` branch.