chore: updated tested up to

Author: [email protected]

readme.txt

@@ -1,8 +1,8 @@
 === Stackable - Page Builder Gutenberg Blocks ===
 Contributors: bfintal, gambitph
 Tags: blocks, gutenberg, gutenberg blocks, page builder, WordPress blocks
-Requires at least: 6.5.5
-Tested up to: 6.8.2
+Requires at least: 6.6.4
+Tested up to: 6.9
 Requires PHP: 7.3
 Stable tag: 3.19.4
 License: GPLv3