Update example with last web-push-php version

Author: Minishlink

README.md

@@ -10,14 +10,15 @@ Navigating through the commits and files will help you build:
 ## Requirements
 - Chrome or Firefox
 - [composer](https://getcomposer.org/)
-- PHP 7.2+
+- PHP 8.0+
     - gmp
     - mbstring
     - curl
     - openssl
 
-PHP 7.1 is no longer maintained, but you can checkout the `v2.x` branch.
-PHP 5.6+ is no longer maintained, but you can checkout the `v1.x` branch.
+PHP 7.2 is no longer maintained, but you can checkout the `v3.x` tags.
+PHP 7.1 is no longer maintained, but you can checkout the `v2.x` tags.
+PHP 5.6+ is no longer maintained, but you can checkout the `v1.x` tags.
 
 ## Installation
 ```bash

composer.json

@@ -10,6 +10,6 @@
         }
     ],
     "require": {
-        "minishlink/web-push": "^6.0.0"
+        "minishlink/web-push": "^8.0.0"
     }
 }