The Lords amendment went to the commons on 13th June and the Commons put in their own amendment which was agreed: this is the text.
https://publications.parliament.uk/pa/bills/lbill/2017-2019/0102/18102-I.pdf
Peers nod through government-backed green Brexit amendment The House of Lords has approved a government-backed amendment to the EU (Withdrawal) Bill that would allow an ‘independent’ watchdog to take the government to court should it infringe its environmental responsibilities.