Add PHP version support to Readme title

Author: Alex Westergaard

README.md

@@ -1,4 +1,4 @@
-# PHP GA4
+# PHP GA4 | PHP 8+
 
 PHP Wrapper for Google Analytics 4 Server Side Tracking of events.
 
@@ -8,7 +8,7 @@ PHP Wrapper for Google Analytics 4 Server Side Tracking of events.
 
 `composer require alexwestergaard/php-ga4`
 
-- [PHP GA4](#php-ga4)
+- [PHP GA4 | PHP 8+](#php-ga4--php-8)
   - [Events](#events)
     - [Default](#default)
     - [E-commerce](#e-commerce)