docs: credit iroh in the lede

Author: cablehead

README.md

@@ -5,7 +5,7 @@
 <h1 align="center">pai-sho</h1>
 
 <p align="center">
-  Forward ports between your own machines, peer to peer.<br>
+  Forward ports between your own machines, peer to peer over <a href="https://github.com/n0-computer/iroh">iroh</a>.<br>
   Neither side needs an account, a public IP, or an open inbound port.<br>
   Only what you grant is reachable.
 </p>