Update phpstan/phpstan requirement from 1.12.5 to 1.12.6 (#188)

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@1.12.5...1.12.6)

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

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

composer.json

@@ -34,7 +34,7 @@
         "symfony/phpunit-bridge": "^7.0",
         "symfony/routing": "^4.4 || ^5.0 || ^6.0 || ^7.0",
         "facile-it/facile-coding-standard": "1.2.0",
-        "phpstan/phpstan": "1.12.5",
+        "phpstan/phpstan": "1.12.6",
         "phpstan/extension-installer": "1.4.3",
         "jangregor/phpstan-prophecy": "1.0.2",
         "phpspec/prophecy": "^1.17",