Readme: Update Tested to value

Author: Clorith

readme.txt

@@ -2,7 +2,7 @@
 Contributors: wordpressdotorg, clorith, azaozz
 Tags: jquery, javascript, update
 Requires at least: 5.4
-Tested up to: 5.7
+Tested up to: 6.3
 Stable tag: 1.3.0
 Requires PHP: 5.6
 License: GPLv2 or later