Update composer.json: Adding PHP 8.4

I haven't tested this, just wanted to make you aware that PHP 8.4 was released meanwhile.

composer.json

@@ -15,7 +15,7 @@
         }
     ],
     "require": {
-        "php": "^7.4 || ~8.0.0 || ~8.1.0 || ~8.2.0 || ~8.3.0",
+        "php": "^7.4 || ~8.0.0 || ~8.1.0 || ~8.2.0 || ~8.3.0 || ~8.4.0",
         "ext-SimpleXML": "*",
         "ext-ctype": "*",
         "ext-dom": "*",