libdrm: 2.4.90 -> 2.4.91

Semi-automatic update generated by https://github.com/ryantm/nixpkgs-update tools.

This update was made based on information from https://repology.org/metapackage/libdrm/versions.

These checks were done:

- built on NixOS
- Warning: no binary found that responded to help or version flags. (This warning appears even if the package isn't expected to have binaries.)
- found 2.4.91 with grep in /nix/store/rff4bpz0j9w5fgxsd5qq1vdv5wpdlwxy-libdrm-2.4.91
- directory tree listing: https://gist.github.com/c13751993f64b3543f93979f9450e5d1

pkgs/development/libraries/libdrm/default.nix

@@ -1,11 +1,11 @@
 { stdenv, fetchurl, pkgconfig, libpthreadstubs, libpciaccess, valgrind-light }:
 
 stdenv.mkDerivation rec {
-  name = "libdrm-2.4.90";
+  name = "libdrm-2.4.91";
 
   src = fetchurl {
     url = "http://dri.freedesktop.org/libdrm/${name}.tar.bz2";
-    sha256 = "db37ec8f1dbaa2c192ad9903c8d0988b858ae88031e96f169bf76aaf705db68b";
+    sha256 = "0068dn47c478vm1lyyhy02gilrpsma0xmcblhvs0dzqyrk80wjk3";
   };
 
   outputs = [ "out" "dev" "bin" ];