Add PHP7.4 compatability via symfony8.0 polyfill

Author: frankdekker

composer.json

@@ -15,7 +15,7 @@
         "php": ">=7.4",
         "composer-plugin-api": "^1.0 || ^2.0",
         "squizlabs/php_codesniffer": "^3.6",
-        "symfony/polyfill-php80": "^1.0"
+        "symfony/polyfill-php80": "^1.15"
     },
     "require-dev": {
         "composer/composer": "^2.0",