Update nixpkgs (lnd 0.8.1 -> lnd 0.9.0, clightning 0.8.0 -> 0.8.1)

test/use-stable-pkgs.patch

@@ -26,16 +26,3 @@ services.connman doesn't exist in stable nixpkgs
  
      # Speed up booting by not waiting for ARP.
      networking.dhcpcd.extraConfig = "noarp";
-
-The test driver assumed coreutils to be in PATH. This fix will be ported to upstream.
---- a/nixos/lib/testing-python.nix
-+++ b/nixos/lib/testing-python.nix
-@@ -155,7 +155,7 @@ in rec {
-             --add-flags "''${vms[*]}" \
-             ${lib.optionalString enableOCR
-               "--prefix PATH : '${ocrProg}/bin:${imagemagick_tiff}/bin'"} \
--            --run "export testScript=\"\$(cat $out/test-script)\"" \
-+            --run "export testScript=\"\$(${coreutils}/bin/cat $out/test-script)\"" \
-             --set VLANS '${toString vlans}'
-           ln -s ${testDriver}/bin/nixos-test-driver $out/bin/nixos-run-vms
-           wrapProgram $out/bin/nixos-run-vms \