Update dependency phpstan/phpstan to ^2.1.5

| datasource | package         | from  | to    |
| ---------- | --------------- | ----- | ----- |
| packagist  | phpstan/phpstan | 2.1.4 | 2.1.5 |

Author: renovate[bot]

composer.json

@@ -16,7 +16,7 @@
         "friendsofphp/php-cs-fixer": "^3.68.5"
     },
     "require-dev": {
-        "phpstan/phpstan": "^2.1.4",
+        "phpstan/phpstan": "^2.1.5",
         "phpstan/phpstan-phpunit": "^2",
         "phpunit/phpunit": "^11.5.7"
     },