When exporting as GIF, add ability to use defined color palette

Hi,

We are working on a pixelart project and most animations needs to be exported as GIF. However, when exporting using GIF, there is currently no way to limit the color palette to the one we are using.

What it does is we do have to manually retouch each exported Rive animation in Aseprite to make sure it respect the color palette.

Could you guys let us define a color palette before exporting to make sure we can use Rive GIF export without having to retouch anything afterwards?

This would save us a lot of time.

Thank you very much!