Bump phpstan/phpstan from 1.12.7 to 2.0.0

Bumps [phpstan/phpstan](https://github.com/phpstan/phpstan) from 1.12.7 to 2.0.0.
- [Release notes](https://github.com/phpstan/phpstan/releases)
- [Changelog](https://github.com/phpstan/phpstan/blob/2.0.x/CHANGELOG.md)
- [Commits](phpstan/phpstan@1.12.7...2.0.0)

---
updated-dependencies:
- dependency-name: phpstan/phpstan
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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

composer.json

@@ -15,6 +15,6 @@
     "elephantio/elephant.io": "4.3.*"
   },
   "require-dev": {
-    "phpstan/phpstan": "^1.10"
+    "phpstan/phpstan": "^2.0"
   }
 }