Bump phpstan/phpstan from 1.12.16 to 2.1.5

Bumps [phpstan/phpstan](https://github.com/phpstan/phpstan) from 1.12.16 to 2.1.5.
- [Release notes](https://github.com/phpstan/phpstan/releases)
- [Changelog](https://github.com/phpstan/phpstan/blob/2.1.x/CHANGELOG.md)
- [Commits](phpstan/phpstan@1.12.16...2.1.5)

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

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

Author: dependabot[bot]

composer.json

@@ -100,7 +100,7 @@
         "pear/versioncontrol_svn": "^0.7.0",
         "phing/phing-composer-configurator": "dev-master",
         "phpmd/phpmd": "^2.14",
-        "phpstan/phpstan": "^0.12.87 || ^1.0",
+        "phpstan/phpstan": "^2.1.5",
         "phpunit/phpunit": "^9.6",
         "psr/http-message": "^2.0",
         "roave/security-advisories": "dev-master",