Update dependency phpstan/phpstan to v2

Author: renovate[bot]

composer.json

@@ -27,7 +27,7 @@
   },
   "require-dev": {
     "phpunit/phpunit": "~6.0 || ~7.0 || ~9.0",
-    "phpstan/phpstan": "^1.0"
+    "phpstan/phpstan": "^2.0"
   },
   "support": {
     "docs": "https://voku.github.io/Arrayy/",