Update phpstan/phpstan-strict-rules requirement from ^1.5.5 to ^1.6.0 (…

…#3027)

Updates the requirements on [phpstan/phpstan-strict-rules](https://github.com/phpstan/phpstan-strict-rules) to permit the latest version.
- [Release notes](https://github.com/phpstan/phpstan-strict-rules/releases)
- [Commits](phpstan/phpstan-strict-rules@1.5.5...1.6.0)

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

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

composer.json

@@ -56,7 +56,7 @@
 		"phpstan/extension-installer": "^1.3.1",
 		"phpstan/phpstan": "^1.11.0",
 		"phpstan/phpstan-phpunit": "^1.4.0",
-		"phpstan/phpstan-strict-rules": "^1.5.5",
+		"phpstan/phpstan-strict-rules": "^1.6.0",
 		"phpunit/phpunit": "^8.5.38",
 		"saschaegerer/phpstan-typo3": "^1.8.4",
 		"squizlabs/php_codesniffer": "^3.9.2",