Breaking change in 4.2.0: withCasts values lost

[guilheb]

I believe PR #202 introdudes a bug with the handling of withCasts.

More precisely, on line 100 of file src/JoinsHelper.php, a new model is created

$query->setModel($model = new $originalModel());

If $model has anything in its casts property (that was defined with a withCasts), it is not preserved when a new model is passed to setModel().

I'm not sure if it's the right solution, but adding this instruction right after seems to solve my problematic scenario.

$model->mergeCasts($originalModel->getCasts());

[luisdalmolin]

This should be fixed in the latest version. Thanks for the report!