Update dependency phpstan/phpstan to ^2.1.16

| datasource | package         | from   | to     |
| ---------- | --------------- | ------ | ------ |
| packagist  | phpstan/phpstan | 2.1.15 | 2.1.16 |

Author: renovate[bot]

composer.json

@@ -16,7 +16,7 @@
         "friendsofphp/php-cs-fixer": "^3.75.0"
     },
     "require-dev": {
-        "phpstan/phpstan": "^2.1.15",
+        "phpstan/phpstan": "^2.1.16",
         "phpstan/phpstan-phpunit": "^2.0.6",
         "phpunit/phpunit": "^12.1.5"
     },