Update php-enum dependency version to ^4.4 (#854)

## Description

Hi,

Versions of `mark-mabe/php-enum` lower than 4.4 emit a warning on PHP 8:

```
PHP Warning: Private methods cannot be final as they are never overridden by other classes
```

so it would be nice to restrict installs to versions that work fine.
There is no BC breaks with this and no change in dependencies.

## Type of Change

- [x] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to not work as expected)
- [ ] Documentation update
- [ ] Code refactoring
- [ ] Other (please describe):

## Checklist

<!-- Mark completed items with an "x" -->

- [x] I have read the [CONTRIBUTING](CONTRIBUTING.md) guidelines
- [x] My code follows the code style of this project
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [x] All new and existing tests pass
- [ ] I have updated the documentation accordingly
- [x] My changes generate no new warnings

Author: emodric

CHANGELOG.md

@@ -6,6 +6,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+### Changed
+- Restricted `mark-mabe/php-enum` dependency to `^4.4` due to lower versions emitting a warning on PHP 8 ([#854](https://github.com/jsonrainbow/json-schema/pull/854))
 
 ## [6.6.2] - 2025-11-28
 ### Changed

composer.json

@@ -29,7 +29,7 @@
     "require": {
         "php": "^7.2 || ^8.0",
         "ext-json": "*",
-        "marc-mabe/php-enum":"^4.0"
+        "marc-mabe/php-enum":"^4.4"
     },
     "require-dev": {
         "friendsofphp/php-cs-fixer": "3.3.0",