gsimplecal: switch to fetchFromGitHub

pkgs/applications/misc/gsimplecal/default.nix

···
-{ lib, stdenv, fetchurl, automake, autoconf, pkg-config, gtk3 }:
+{ lib, stdenv, fetchFromGitHub, automake, autoconf, pkg-config, gtk3 }:
 
 stdenv.mkDerivation rec {
   pname = "gsimplecal";
   version = "2.2";
 
-  src = fetchurl {
-    url = "https://github.com/dmedvinsky/gsimplecal/archive/v${version}.tar.gz";
-    sha256 = "sha256-f19cnTX83LZT2d01B1EdWSaHcfHqpFPTo5glYkAokq8=";
+  src = fetchFromGitHub {
+    owner = "dmedvinsky";
+    repo = "gsimplecal";
+    rev = "v${version}";
+    sha256 = "sha256-r7OitN7WSY7vxpQCraLyokgUNgvaVFjE17ghBGgxzuM=";
   };
 
   postPatch = ''