moved doc/contributing.md to CONTRIBUTING.md

Author: m3dwards

docs/contributing.md renamed to CONTRIBUTING.md

@@ -23,6 +23,6 @@ Monitor and analyze the emergent behaviors of Bitcoin networks.
 - [Scaling](/docs/scaling.md)
 - [Connecting to local nodes](https://github.com/bitcoin-dev-project/warnet/blob/main/docs/)
 - [Understanding network configuration](/docs/config.md)
-- [Contributing](/docs/contributing.md)
+- [Contributing](CONTRIBUTING.md)
 
 ![warnet-art](https://raw.githubusercontent.com/bitcoin-dev-project/warnet/main/docs/machines.webp)