chore: Remove unused dev dependency.

Author: drupol

composer.json

@@ -28,7 +28,6 @@
         "loophp/launcher": "^2.2.2",
         "microsoft/tolerant-php-parser": "^0.0.20",
         "nikic/php-parser": "^4",
-        "phpbench/phpbench": "^0.16.10",
         "phpspec/phpspec": "^7"
     },
     "config": {