tools: update nixpkgs-unstable to ab9fbbcf4858bd6d40ba2bbec37ceb4ab6e

Author: nodejs-github-bot

tools/nix/pkgs.nix

@@ -1,10 +1,10 @@
 arg:
 let
   repo = "https://github.com/NixOS/nixpkgs";
-  rev = "be5afa0fcb31f0a96bf9ecba05a516c66fcd8114";
+  rev = "ab9fbbcf4858bd6d40ba2bbec37ceb4ab6e1f562";
   nixpkgs = import (builtins.fetchTarball {
     url = "${repo}/archive/${rev}.tar.gz";
-    sha256 = "0jm942f32ih264hmna7rhjn8964sid0sn53jwrpc73s2vyvqs7kc";
+    sha256 = "1jkl1sjn89s8sd7x99kv0j2khhbz5vzpyf3iiscq3r0ybnjlj1wq";
   }) arg;
 in
 nixpkgs