Add format as a supported property for the DatePicker widget

[host138]

Hello, i have a problem.
When i write format: d.m.Y in the fields.yaml and then use builder plugin, it rewrites fields.yaml file, but at the same time the builder doesn't have format field.
How to use it corect without rewriting?
Thank's.

[LukeTowers]

You would have to add format as an available property to the date picker widget in the StandardControlsRegistry here: https://github.com/rainlab/builder-plugin/blob/master/classes/StandardControlsRegistry.php#L638. Feel free to make a PR to do that.

[bennothommo]

Fixed by #288.