The latest RelayHub is live at this address: 0xD216153c06E857cD7f72665E0aF1d7D82172F494.
If there is a new RelayHub then it will be at a new address.
There is a single instance of the RelayHub in the whole network and the address will be the same in each network.
https://docs.openzeppelin.com/openzeppelin/gsn/what-is-the-gsn