Bump the support lifetime by 2 years this time to reduce anxiety

Author: defuse

README.md

@@ -20,7 +20,7 @@ version of PHP could lead to security vulnerabilities.
 
 The current version of `php-encryption` is v2.3.1. This library is expected to
 remain stable and supported by its authors with security and bugfixes until at
-least January 1st, 2022.
+least January 1st, 2024.
 
 The library is a joint effort between [Taylor Hornby](https://defuse.ca/) and
 [Scott Arciszewski](https://paragonie.com/blog/author/scott-arcizewski) as well