Bump tested up to 6.4

Author: westonruter

README.md

@@ -7,7 +7,7 @@ WordPress feature plugin to bring Progressive Web App (PWA) capabilities to Core
 **Contributors:** [google](https://profiles.wordpress.org/google), [xwp](https://profiles.wordpress.org/xwp), [rtcamp](https://profiles.wordpress.org/rtcamp), [westonruter](https://profiles.wordpress.org/westonruter), [albertomedina](https://profiles.wordpress.org/albertomedina)  
 **Tags:** [pwa](https://wordpress.org/plugins/tags/pwa), [progressive web apps](https://wordpress.org/plugins/tags/progressive-web-apps), [service workers](https://wordpress.org/plugins/tags/service-workers), [web app manifest](https://wordpress.org/plugins/tags/web-app-manifest)  
 **Requires at least:** 6.3  
-**Tested up to:** 6.3  
+**Tested up to:** 6.4  
 **Stable tag:** 0.8.0  
 **License:** [GPLv2 or later](http://www.gnu.org/licenses/gpl-2.0.html)  
 **Requires PHP:** 7.0