updated version to 1.20.1

pkgs/tools/misc/ipxe/default.nix

@@ -1,11 +1,9 @@
-{ stdenv, lib, fetchgit, perl, cdrkit, syslinux, xz, openssl, gnu-efi, mtools
+{ stdenv, lib, fetchFromGitHub, perl, cdrkit, syslinux, xz, openssl, gnu-efi, mtools
 , embedScript ? null
 , additionalTargets ? {}
 }:
 
 let
-  date = "20190318";
-  rev = "ebf2eaf515e46abd43bc798e7e4ba77bfe529218";
   targets = additionalTargets // lib.optionalAttrs stdenv.isx86_64 {
     "bin-x86_64-efi/ipxe.efi" = null;
     "bin-x86_64-efi/ipxe.efirom" = null;
@@ -19,15 +17,17 @@ let
   };
 in
 
-stdenv.mkDerivation {
-  name = "ipxe-${date}-${builtins.substring 0 7 rev}";
+stdenv.mkDerivation rec {
+  pname = "ipxe";
+  version = "1.20.1";
 
   nativeBuildInputs = [ perl cdrkit syslinux xz openssl gnu-efi mtools ];
 
-  src = fetchgit {
-    url = https://git.ipxe.org/ipxe.git;
-    sha256 = "0if3m8h1nfxy4n37cwlfbc5kand52290v80m4zvjppc81im3nr5g";
-    inherit rev;
+  src = fetchFromGitHub {
+    owner = "ipxe";
+    repo = "ipxe";
+    rev = "v${version}";
+    sha256 = "0w7h7y97gj9nqvbmsg1zp6zj5mpbbpckqbbx7bpp6k3ahy5fk8zp";
   };
 
   # not possible due to assembler code