Update phpstan/phpstan requirement from ^1.10 to ^2.0

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/2.0.x/CHANGELOG.md)
- [Commits](phpstan/phpstan@1.10.0...2.0.3)

---
updated-dependencies:
- dependency-name: phpstan/phpstan
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <support@github.com>

composer.json

@@ -18,7 +18,7 @@
     },
     "require-dev" : {
         "friendsofphp/php-cs-fixer": "3.65.0",
-        "phpstan/phpstan": "^1.10"
+        "phpstan/phpstan": "^2.0"
     },
     "replace" : {
         "jeromeschneider/baikal" : "self.version"