chore(deps-dev): update codeigniter/phpstan-codeigniter requirement

Updates the requirements on [codeigniter/phpstan-codeigniter](https://github.com/CodeIgniter/phpstan-codeigniter) to permit the latest version.

Updates `codeigniter/phpstan-codeigniter` to 2.1.0
- [Release notes](https://github.com/CodeIgniter/phpstan-codeigniter/releases)
- [Changelog](https://github.com/CodeIgniter/phpstan-codeigniter/blob/2.x/CHANGELOG.md)
- [Commits](CodeIgniter/phpstan-codeigniter@v1.5.0...v2.1.0)

---
updated-dependencies:
- dependency-name: codeigniter/phpstan-codeigniter
  dependency-version: 2.1.0
  dependency-type: direct:development
  dependency-group: composer-dependencies
...

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

Author: dependabot[bot]

composer.json

@@ -18,7 +18,7 @@
     },
     "require-dev": {
         "boundwize/structarmed": "0.13.4",
-        "codeigniter/phpstan-codeigniter": "^1.5",
+        "codeigniter/phpstan-codeigniter": "^2.1",
         "fakerphp/faker": "^1.24",
         "kint-php/kint": "^6.1",
         "mikey179/vfsstream": "^1.6.12",