Fix comp php 8

[rabauss]

• Unlock nickdnk/graph-sdk v7 - see: https://github.com/nickdnk/php-graph-sdk/blob/master/CHANGELOG.md#7x-unofficial
• Fix type error in cron if message is null

[rabauss]

@MDevster what about this PR?

[MDevster]

@rabauss 🤗 Released as 2.12.0