jbig2enc: switch to fetchFromGitHub

pkgs/tools/graphics/jbig2enc/default.nix

···
-{ lib, stdenv, fetchurl, leptonica, zlib, libwebp, giflib, libjpeg, libpng, libtiff }:
+{ lib, stdenv, fetchFromGitHub, leptonica, zlib, libwebp, giflib, libjpeg, libpng, libtiff }:
 
 stdenv.mkDerivation rec {
   pname = "jbig2enc";
   version = "0.28";
 
-  src = fetchurl {
-    url = "https://github.com/agl/jbig2enc/archive/${version}-dist.tar.gz";
-    sha256 = "1wc0lmqz4jag3rhhk1xczlqpfv2qqp3fz7wzic2lba3vsbi1rrw3";
+  src = fetchFromGitHub {
+    owner = "agl";
+    repo = "jbig2enc";
+    rev = "${version}-dist";
+    hash = "sha256-Y3IVTjvO5tqn/O076y/llnTyenKpbx1WyT/JFZ/s0VY=";
   };
 
   propagatedBuildInputs = [ leptonica zlib libwebp giflib libjpeg libpng libtiff ];