External Libraries: Update random_compat to version 2.0.21.

The latest release includes improved compatibility with PHP 8.1, as well as some bug fixes for Windows platforms.

Release notes:
https://github.com/paragonie/random_compat/releases/tag/v2.0.21

For a full list of changes in this update, see the random_compat GitHub:
https://github.com/paragonie/random_compat/compare/v2.0.11...v2.0.21

Follow-up to [42130].

Props jrf, paragoninitiativeenterprises.
Fixes #55181.

git-svn-id: https://develop.svn.wordpress.org/trunk@52742 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/random_compat/error_polyfill.php

@@ -1,12 +1,12 @@
 <?php
 /**
- * Random_* Compatibility Library 
+ * Random_* Compatibility Library
  * for using the new PHP 7 random_* API in PHP 5 projects
- * 
+ *
  * The MIT License (MIT)
  *
- * Copyright (c) 2015 - 2017 Paragon Initiative Enterprises
- * 
+ * Copyright (c) 2015 - 2018 Paragon Initiative Enterprises
+ *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
  * in the Software without restriction, including without limitation the rights
@@ -30,7 +30,7 @@ if (!class_exists('Error', false)) {
     // We can't really avoid making this extend Exception in PHP 5.
     class Error extends Exception
     {
-        
+
     }
 }
 
@@ -38,12 +38,12 @@ if (!class_exists('TypeError', false)) {
     if (is_subclass_of('Error', 'Exception')) {
         class TypeError extends Error
         {
-            
+
         }
     } else {
         class TypeError extends Exception
         {
-            
+
         }
     }
 }