postfixadmin: stdenv.lib -> lib

pkgs/servers/postfixadmin/default.nix

···
-{ fetchFromGitHub, stdenv }:
+{ fetchFromGitHub, stdenv, lib }:
 
 stdenv.mkDerivation rec {
   pname = "postfixadmin";
···
   meta = {
     description = "Web based virtual user administration interface for Postfix mail servers";
     homepage = "https://postfixadmin.sourceforge.io/";
-    maintainers = with stdenv.lib.maintainers; [ globin ];
-    license = stdenv.lib.licenses.gpl2Plus;
-    platforms = stdenv.lib.platforms.all;
+    maintainers = with lib.maintainers; [ globin ];
+    license = lib.licenses.gpl2Plus;
+    platforms = lib.platforms.all;
   };
 }