This combination has been failing lately because of no install candidate.
1 patch for repository http://darcs.net/screened:
patch 9d0971d4c8e0f2a959e1fab822cdeb154a677d4b
Author: Ben Franksen <ben.franksen@online.de>
Date: Fri Jun 11 20:38:09 CEST 2021
* ci: exclude macOS-10.15 && ghc-8.10.4