chore(deps): update dependency phpstan/phpstan to v2.1.6 (#207)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

composer.json

@@ -28,7 +28,7 @@
         "doctrine/coding-standard": "^12.0",
         "infection/infection": "^0.29.0",
         "phpstan/extension-installer": "^1.1",
-        "phpstan/phpstan": "2.1.4",
+        "phpstan/phpstan": "2.1.6",
         "phpstan/phpstan-phpunit": "2.0.4",
         "phpstan/phpstan-strict-rules": "2.0.3",
         "phpunit/phpunit": "^11.0",