these 2 derivations will be built:
  /nix/store/6ffkvw235c3zah21pkskr2mb9vhsmj4w-nixos-test-driver-pg_repack.drv
  /nix/store/dk8lpv9miwx1p8smanvy5ibikbz1ilp8-vm-test-run-pg_repack.drv