Update README to reflect PHP versions supported

Author: ramsey

README.md

@@ -24,16 +24,10 @@ This package is compliant with [PSR-1][], [PSR-2][], [PSR-4][], and [PSR-7][]. I
 
 We support the following versions of PHP:
 
+* PHP 8.4
 * PHP 8.3
 * PHP 8.2
 * PHP 8.1
-* PHP 8.0
-* PHP 7.4
-* PHP 7.3
-* PHP 7.2
-* PHP 7.1
-* PHP 7.0
-* PHP 5.6
 
 ## Provider Clients