composer.json: upgrade PHPStan to major version 2

Author: davidrjenni

composer.json

@@ -46,10 +46,10 @@
     },
     "require-dev": {
         "phpstan/extension-installer": "^1.2",
-        "phpstan/phpstan": "^1.10",
-        "phpstan/phpstan-deprecation-rules": "^1.1",
-        "phpstan/phpstan-phpunit": "^1.3",
-        "phpstan/phpstan-strict-rules": "^1.5",
+        "phpstan/phpstan": "^2.1",
+        "phpstan/phpstan-deprecation-rules": "^2.0",
+        "phpstan/phpstan-phpunit": "^2.0",
+        "phpstan/phpstan-strict-rules": "^2.0",
         "phpunit/phpunit": "^12.0",
         "slevomat/coding-standard": "^8.11",
         "squizlabs/php_codesniffer": "^3.7"