Carbon object in Entity::toArray() about analogue

[RemiCollin]

You're right as in the update process, the timestamps attributes are set with Carbon::now() which the Illuminate Query translate into the correct datetime format, but the inverse is not true, as date attribute is hydrated as a string, which leads to this inconsistency.

Several ways to solve this :

1. Cast the carbon object to string after the update/create query.
2. Hydrate date attributes with instance of Carbon.
3. Add a $dates attribute to the entity map to customize this behaviour. If the attribute is contained in the array, it will be hydrated with an instance of Carbon, if it's not with a string. Of course this raises the question of which behaviour to choose as a default for the timestamps. I'd tend to go on the Carbon side, but i'd like to make some benchmarks to see if it's not too costy in terms of hydration performance.

That's for the big picture.

Concerning the toArray() method, I think we can simply test if the attribute is an instance of carbon, and casting it to string if it's so. This will work whatever option we choose for the hydration behaviour. Feel free to PR it ;)

[RemiCollin]

Fixed the casting in v2.1.7 release