update kirby to v5 and add refresh cache panel view button

public/kirby/src/Http/Header.php

@@ -287,15 +287,14 @@ class Header
 	 */
 	public static function download(array $params = []): void
 	{
-		$defaults = [
+		$options = [
 			'name'     => 'download',
 			'size'     => false,
 			'mime'     => 'application/force-download',
-			'modified' => time()
+			'modified' => time(),
+			...$params
 		];
 
-		$options = array_merge($defaults, $params);
-
 		header('Pragma: public');
 		header('Cache-Control: no-cache, no-store, must-revalidate');
 		header('Last-Modified: ' . gmdate('D, d M Y H:i:s', $options['modified']) . ' GMT');