chore: allow compatibility with PHPSpec 8.x

Author: shulard

composer.json

@@ -44,7 +44,7 @@
     },
     "require": {
         "php": ">= 7.3",
-        "phpspec/phpspec": "^6.0 || ^7.0",
+        "phpspec/phpspec": "^6.0 || ^7.0 || ^8.0",
         "phpunit/php-code-coverage": "^9.2 || ^10.0 || ^11.0",
         "phpunit/php-file-iterator": "^3.0 || ^4.0 || ^5.0"
     },