build(deps): update phpstan/phpstan requirement in /tools

Updates the requirements on [phpstan/phpstan](https://github.com/phpstan/phpstan) to permit the latest version.
- [Release notes](https://github.com/phpstan/phpstan/releases)
- [Changelog](https://github.com/phpstan/phpstan/blob/2.1.x/CHANGELOG.md)
- [Commits](phpstan/phpstan@2.0.0...2.1.17)

---
updated-dependencies:
- dependency-name: phpstan/phpstan
  dependency-version: 2.1.17
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

tools/composer.json

@@ -2,7 +2,7 @@
   "require": {
     "friendsofphp/php-cs-fixer": "^3.75",
     "phpstan/extension-installer": "^1.4",
-    "phpstan/phpstan": "^2.0",
+    "phpstan/phpstan": "^2.1",
     "phpstan/phpstan-phpunit": "^2.0",
     "staabm/annotate-pull-request-from-checkstyle": "^1.8",
     "rector/rector": "^2.0"