composer(deps-dev): update phpstan/phpstan requirement

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/1.11.x/CHANGELOG.md)
- [Commits](phpstan/phpstan@1.10.21...1.10.26)

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

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

composer.json

@@ -34,7 +34,7 @@
     "mimmi20/coding-standard": "^5.1.7",
     "nikic/php-parser": "^v4.16.0",
     "phpstan/extension-installer": "^1.3.1",
-    "phpstan/phpstan": "^1.10.21",
+    "phpstan/phpstan": "^1.10.26",
     "phpstan/phpstan-deprecation-rules": "^1.1.3",
     "phpstan/phpstan-phpunit": "^1.3.13",
     "phpunit/phpunit": "^10.2.6",