Added updated pandant required versions (#5961)

pendant/readme.txt

@@ -1,6 +1,6 @@
 === Pendant ===
 Contributors: Automattic
-Requires at least: 5.8
+Requires at least: 5.9
 Tested up to: 5.9
 Requires PHP: 5.7
 License: GPLv2 or later

pendant/style.css

@@ -4,9 +4,10 @@ Theme URI: https://github.com/Automattic/themes/tree/trunk/pendant
 Author: Automattic
 Author URI: https://automattic.com
 Description: An elegant product-focused theme
-Requires at least: 5.8
+Requires at least: 5.9
 Tested up to: 5.9
 Requires PHP: 5.7
+Requires Gutenberg: 13.1
 Version: 1.0.0
 License: GNU General Public License v2 or later
 License URI: https://raw.githubusercontent.com/Automattic/themes/trunk/LICENSE