Class eZ\Bundle\EzPublishLegacyBundle\Composer\ScriptHandler extends Sensio\Bundle\DistributionBundle\Composer\ScriptHandler but it's incompatible with it. It overrides method installAssets but uses wrong type hint.

eZ\Bundle\EzPublishLegacyBundle\Composer\ScriptHandler:

public static function installAssets( CommandEvent $event )

Sensio\Bundle\DistributionBundle\Composer\ScriptHandler:

public static function installAssets(Event $event)

The result of this issue is that you get

[ErrorException]
Declaration of eZ\Bundle\EzPublishLegacyBundle\Composer\ScriptHandler::installAssets() should be compatible with Sensio\Bundle\DistributionBundle\Composer\ScriptHandler::installAssets(Composer\Script\Event $event)

While doing composer update

Steps to reproduce:
1. Composer update on 5.4 version

Note:
This might be issue with other 5.4 versions (older than 5.4.9) as well