That is node-red-node-pi-gpio, not node-red-node-rpi-gpio.
In addition to @knolleary's comment I think you also have to include a copy of the original license and can't impose any restrictions on what that license says. Check the licence with the node and see what it says.
I need to change the author field to me since I wouldn't want questions going to Dave.
The license is Apache 2.0 which is pretty permissible so I don't think there's any issue there. I've been a Fedora packager for over 10 years and while I don't consider myself a license expert, I have been exposed to many (GPL, BSD, Apache, etc).
Adding something to the README is easy enough, I just wasn't sure if there was a best practice already established