Fix up version

Author: dereuromark

README.md

@@ -24,10 +24,10 @@ For details and older versions see [version map](https://github.com/cakephp/debu
 
 * Install the plugin with [Composer](https://getcomposer.org/) from your CakePHP Project's ROOT directory (where the **composer.json** file is located)
 ```sh
-php composer.phar require --dev cakephp/debug_kit:"^4.0"
+php composer.phar require --dev cakephp/debug_kit:"^5.0"
 ```
 
-* [Load the plugin](https://book.cakephp.org/4/en/plugins.html#loading-a-plugin)
+* [Load the plugin](https://book.cakephp.org/5/en/plugins.html#loading-a-plugin)
 ```php
 // src/Application.php
 $this->addPlugin('DebugKit');