oro/platform-serialised-fields 5.0.2 should require oro/platform 5.0.8+

[NN-Antadis]

Summary
When updating my ORO application, I ran into a problem with an unknown class.

Steps to reproduce
From a 5.0.1 enterprise application running, I updated all oro dependencies.
I ended up with oro/platform-serialised-fields 5.0.2 and oro/platform 5.0.5.

Oro\Bundle\EntitySerializedFieldsBundle\Async\Topic\SerializedAttributeRemovedFromFamilyTopic extends Oro\Bundle\EntityConfigBundle\Async\Topic\AttributeRemovedFromFamilyTopic which is only created in oro/platform 5.0.8

https://github.com/oroinc/platform/tree/5.0.8/src/Oro/Bundle/EntityConfigBundle/Async/Topic
versus
https://github.com/oroinc/platform/tree/5.0.7/src/Oro/Bundle/EntityConfigBundle/Async/Topic [404]

and

https://github.com/oroinc/OroEntitySerializedFieldsBundle/blob/5.0.2/Async/Topic/SerializedAttributeRemovedFromFamilyTopic.php
was created in oro/platform-serialised-fields 5.0.2

See composer.json for oro/platform-serialised-fields, it should mention oro/platform 5.0.8+ : https://github.com/oroinc/OroEntitySerializedFieldsBundle/blob/5.0.2/composer.json

Fix for application developers
Force oro/platform to 5.0.8+ in composer.json then update the package with composer, including dependencies