Update dependency phpstan/phpstan-phpunit to ^2.0.16

| datasource | package                 | from   | to     |
| ---------- | ----------------------- | ------ | ------ |
| packagist  | phpstan/phpstan-phpunit | 2.0.15 | 2.0.16 |

Author: renovate[bot]

composer.json

@@ -15,7 +15,7 @@
     },
     "require-dev": {
         "phpstan/phpstan": "^2.1.39",
-        "phpstan/phpstan-phpunit": "^2.0.15",
+        "phpstan/phpstan-phpunit": "^2.0.16",
         "phpstan/phpstan-strict-rules": "^2.0.10",
         "phpunit/phpunit": "^13.0.2",
         "slam/php-cs-fixer-extensions": "^3.14.0",