Fix IRC channel link

Use #sway-devel instead of #sway

README.md

@@ -8,7 +8,7 @@ This is a WIP: [status](https://github.com/SirCmpwn/wlroots/issues/9)
 ## Contributing
 
 Development is organized in our [IRC
-channel](http://webchat.freenode.net/?channels=sway&uio=d4), #sway on
+channel](http://webchat.freenode.net/?channels=sway-devel&uio=d4), #sway-devel on
 irc.freenode.net. Join us and ask how you can help!
 
 ## Building