MySQL system requirements

[ausi]

After contao/contao#6859 (comment) is merged, if you install Contao 5.6 and you have a MySQL version below 5.7.9 or a MariaDB version below 10.4.3 you would need to add a conflict for "doctrine/dbal": ">=4.0".
Should we document that somehow?
Or should we just list 5.7.9 and 10.4.3 as a minimum requirement for Contao 5.6?

[zoglo]

Or should we just list 5.7.9 and 10.4.3 as a minimum requirement for Contao 5.6?

I think this should suffice. Even if it's documented that you could add a conflict to doctrine, most people would still ask the question.

[Toflar]

Or should we just list 5.7.9 and 10.4.3 as a minimum requirement for Contao 5.6?

I think this is the way to go.

[fritzmg]

I also think we should just list these versions as the minimum requirement.