Update dependency phpstan/phpstan-phpunit to v2

Author: renovate[bot]

composer.json

@@ -32,7 +32,7 @@
         "wyrihaximus/ticking-promise": "^3"
     },
     "require-dev": {
-        "phpstan/phpstan-phpunit": "^0.12.22",
+        "phpstan/phpstan-phpunit": "^2.0.0",
         "wyrihaximus/async-test-utilities": "^4.2.2"
     },
     "autoload": {