Add cast on migration

[vdauchy]

Hi @rubenvanassche ,

This is my PR following #49 .

This make the migrations 'castable' using the global casts.

NOTES:

• As this change the Type passed to the update's closure, this might be concidered as breaking change.
• There is many use of optional() helper, those could be replaced by ?-> when php 8 is only supported.
• To reduce breaking change casts are only set on objects created or updated.
• Since now we have access to settings classes in migrations, we could enforce that groups and names match existing group class and there properties (to detect typos or non exting group/properties), maybe as a futur feature...

[rubenvanassche]

This is looking great! Just one small comment

[rubenvanassche]

As this change the Type passed to the update's closure, this might be concidered as breaking change.

Yeah, I'm not sure how many users already use this functionality so tagging a major version is maybe a big step

There is many use of optional() helper, those could be replaced by ?-> when php 8 is only supported.

Hmm, makes me want to make the package PHP 8 only 😄

To reduce breaking change casts are only set on objects created or updated.

👍

Since now we have access to settings classes in migrations, we could enforce that groups and names match existing group class and there properties (to detect typos or non exting group/properties), maybe as a futur feature...

That's actually a great idea!

[rubenvanassche]

Looking great @vdauchy, thanks!