disper: stay with python2

pkgs/tools/misc/disper/default.nix

···
-{ lib, stdenv, fetchFromGitHub, python, xorg, makeWrapper }:
+{ lib, stdenv, fetchFromGitHub, python2, xorg, makeWrapper }:
 
 stdenv.mkDerivation rec {
   pname = "disper";
···
 
   nativeBuildInputs = [ makeWrapper ];
 
-  buildInputs = [ python ];
+  strictDeps = true;
+
+  buildInputs = [ python2 ];
 
   preConfigure = ''
     export makeFlags="PREFIX=$out"