Update squizlabs/php_codesniffer requirement from ^3.10 to ^4.0

Updates the requirements on [squizlabs/php_codesniffer](https://github.com/PHPCSStandards/PHP_CodeSniffer) to permit the latest version.
- [Release notes](https://github.com/PHPCSStandards/PHP_CodeSniffer/releases)
- [Changelog](https://github.com/PHPCSStandards/PHP_CodeSniffer/blob/4.x/CHANGELOG-4.x.md)
- [Commits](PHPCSStandards/PHP_CodeSniffer@3.10.0...4.0.0)

---
updated-dependencies:
- dependency-name: squizlabs/php_codesniffer
  dependency-version: 4.0.0
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

composer.json

@@ -26,7 +26,7 @@
     "phpstan/phpstan": "^2",
     "phpunit/phpunit": "^9 || ^10",
     "slim/psr7": "^1.6",
-    "squizlabs/php_codesniffer": "^3.10"
+    "squizlabs/php_codesniffer": "^4.0"
   },
   "autoload": {
     "psr-4": {