feat(req): add php 8 requirement in composer.json

Author: Boris van Katwijk

composer.json

@@ -14,6 +14,9 @@
         }
     ],
     "minimum-stability": "dev",
+    "require": {
+        "php": "^8"
+    },
     "autoload": {
         "files": [
             "registration.php"
@@ -22,4 +25,4 @@
             "Experius\\WysiwygDownloads\\": ""
         }
     }
-}
+}