refactor: Plugin class to SearchFilterPlugin and update deprecation warnings

Author: arodu

src/Plugin.php

@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+namespace CakeDC\SearchFilter;
+
+/**
+ * @deprecated 5.3.0 This class will be removed in a future version of CakePHP
+ * Use \CakeDC\SearchFilter\SearchFilterPlugin instead.
+ */
+class Plugin extends SearchFilterPlugin
+{
+    /**
+     * @param array $config Plugin configuration.
+     */
+    public function __construct(array $config = [])
+    {
+        deprecationWarning(
+            '5.3.0',
+            'The `Plugin` class is deprecated. Use `\CakeDC\SearchFilter\SearchFilterPlugin` instead ' .
+                'to comply with CakePHP 5.3+ naming conventions.'
+        );
+        parent::__construct($config);
+    }
+}