discord: 0.0.19 -> 0.0.20

{ branch ? "stable", callPackage, fetchurl, lib, stdenv }:

let

  versions = if stdenv.isLinux then {

    stable = "0.0.19";

    stable = "0.0.20";

    ptb = "0.0.29";

    canary = "0.0.139";

  } else {

    x86_64-linux = {

      stable = fetchurl {

        url = "https://dl.discordapp.net/apps/linux/${version}/discord-${version}.tar.gz";

        sha256 = "GfSyddbGF8WA6JmHo4tUM27cyHV5kRAyrEiZe1jbA5A=";

        sha256 = "3f7yuxigEF3e8qhCetCHKBtV4XUHsx/iYiaCCXjspYw=";

      };

      ptb = fetchurl {

        url = "https://dl-ptb.discordapp.net/apps/linux/${version}/discord-ptb-${version}.tar.gz";