Prevent installation of older marc-mabe/php-enum versions

Ref: https://github.com/Roave/BackwardCompatibilityCheck/actions/runs/18657635613/job/53190540967?pr=929#step:3:590

Helps with:

```
 PHP Warning:  Private methods cannot be final as they are never overridden by other classes in /github/workspace/vendor/marc-mabe/php-enum/src/Enum.php on line 82
.................................................
Warning: Private methods cannot be final as they are never overridden by other classes in /github/workspace/vendor/marc-mabe/php-enum/src/Enum.php on line 82
```

Author: Ocramius

composer.json

@@ -39,7 +39,8 @@
     },
     "conflict": {
         "revolt/event-loop": "<0.2.5",
-        "symfony/process": "<5.3.7"
+        "symfony/process": "<5.3.7",
+        "marc-mabe/php-enum": "<4.7.2"
     },
     "autoload": {
         "psr-4": {