Update PHPStan packages to v2

Author: text-html-renovate[bot]

Diff for: composer.json

@@ -17,9 +17,9 @@
     "require-dev": {
         "squizlabs/php_codesniffer": "^3.6",
         "slevomat/coding-standard": "^8.0",
-        "phpstan/phpstan": "^1.12",
+        "phpstan/phpstan": "^2.0",
         "phpstan/extension-installer": "^1.1",
-        "phpstan/phpstan-strict-rules": "^1.1",
+        "phpstan/phpstan-strict-rules": "^2.0",
         "texthtml/doctest": "^0.2"
     },
     "config": {