Update dependency phpunit/phpunit to v12

| datasource | package         | from   | to     |
| ---------- | --------------- | ------ | ------ |
| packagist  | phpunit/phpunit | 9.6.21 | 12.0.0 |

Author: renovate[bot]

composer.json

@@ -33,7 +33,7 @@
         "phpstan/phpstan-deprecation-rules": "^1.1.3",
         "phpstan/phpstan-phpunit": "^1.3.13",
         "phpstan/phpstan-strict-rules": "^1.5.1",
-        "phpunit/phpunit": "^9.6.9"
+        "phpunit/phpunit": "^12.0.0"
     },
     "autoload": {
         "psr-4": {