[XFA] MG Media Of The Month - XF2 5.0.0

Corrected bugs:

• Change back of a fix from previous version that wasn't one.

Core version 1.5.1 needs to be installed prior to upgrading.

Corrected bugs:

• InvalidArgumentException: Attempted to convert NULL to string/binary [username]
• Notification threads are not posted in the right forum
• Incorrect date format taken into account in thread title

Corrected bugs:

• InvalidArgumentException: Attempted to convert NULL to string/binary [username] src/XF/Mvc/Entity/Entity.php:688
• ErrorException: Fatal Error: Cannot use isset() on the result of a function call -> Leading to issues with thread notifications

Corrected bugs:

• ErrorException: Fatal Error: Cannot use isset() on the result of a function call src/addons/XFA/XFMGMediaOfTheMonth/Cron/XFMGMediaOfTheMonth.php
• ErrorException: Fatal Error: Cannot use isset() on the result of a function call src/addons/XFA/XFMGMediaOfTheMonth/Cron/XFMGMediaOfTheMonth/Listener.php

Modification:

• [XFA] Core min. version requirement changed to 1.5.1