[buoh] nix: update Nixpkgs reference

[Jan Tojnar <jtojnar src gnome org>]

commit 49f5291bbe1a4cd7a08d217db01383c657f3fd3a
Author: Jan Tojnar <jtojnar gmail com>
Date:   Fri May 28 17:09:14 2021 +0200

    nix: update Nixpkgs reference

 default.nix | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/default.nix b/default.nix
index 11dd335..371055d 100644
--- a/default.nix
+++ b/default.nix
@@ -36,8 +36,8 @@ Or to speed up the build by not running the test suite:
 
 { pkgs ?
     (import (fetchTarball {
-      url = "https://github.com/NixOS/nixpkgs/archive/9c304aa09649e6ccbbd58d6a4bf6da8a29e84304.tar.gz";;
-      sha256 = "0ff71213j49nj0wn0rdydv9ahxm1lkb90k8d17rziyqyfh3j11rv";
+      url = "https://github.com/NixOS/nixpkgs/archive/5658fadedb748cb0bdbcb569a53bd6065a5704a9.tar.gz";;
+      sha256 = "1kpmhd9v5a3fbwq86spd1p5s4npfd1jrjl14kl6h1n1l1qd6cbp6";
     }) {})
 , doCheck ? true
 , shell ? false