Update stable tag to 6.4.2

Author: kraftbj

readme.txt

@@ -4,7 +4,7 @@ Tags: fields, custom fields, meta, scf
 Requires at least: 6.0
 Tested up to: 6.7
 Requires PHP: 7.4
-Stable tag: 6.4.1
+.4.2
 License: GPLv2 or later
 License URI: https://www.gnu.org/licenses/gpl-2.0.html