fetchFromGitHub: add option for custom name

This is necessary when the rev name contains a "/"

pkgs/tools/backup/bareos/default.nix

@@ -1,4 +1,4 @@
-{ stdenv, fetchzip, pkgconfig, nettools, gettext, readline, openssl, python
+{ stdenv, fetchFromGitHub, pkgconfig, nettools, gettext, readline, openssl, python
 , ncurses ? null
 , sqlite ? null, postgresql ? null, mysql ? null, libcap ? null
 , zlib ? null, lzo ? null, acl ? null, ceph ? null
@@ -11,8 +11,11 @@ stdenv.mkDerivation rec {
   name = "bareos-${version}";
   version = "14.2.2";
 
-  src = fetchzip {
-    url = "https://github.com/bareos/bareos/archive/Release/${version}.tar.gz";
+  src = fetchFromGitHub {
+    owner = "bareos";
+    repo = "bareos";
+    rev = "Release/${version}";
+    name = "${name}-src";
     sha256 = "12605jibvj6kdp15s8jpzb9fw1mfm53npf8ib2jfn1r4hvhdrl4j";
   };