Update phpstan/phpstan-phpunit requirement from 1.1.1 to 1.4.0

Updates the requirements on [phpstan/phpstan-phpunit](https://github.com/phpstan/phpstan-phpunit) to permit the latest version.
- [Release notes](https://github.com/phpstan/phpstan-phpunit/releases)
- [Commits](phpstan/phpstan-phpunit@1.1.1...1.4.0)

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

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

Author: dependabot[bot]

composer.json

@@ -41,7 +41,7 @@
         "matthiasnoback/symfony-dependency-injection-test": "^5.0",
         "phpspec/phpspec": "^7.0",
         "phpstan/phpstan": "1.11.8",
-        "phpstan/phpstan-phpunit": "1.1.1",
+        "phpstan/phpstan-phpunit": "1.4.0",
         "phpstan/phpstan-webmozart-assert": "1.2.0",
         "phpunit/phpunit": "^10.5",
         "rector/rector": "^0.13.6",