Add `package` parameter to `RiveAnimation.asset()` for package support

[eli1stark]

Problem

RiveAnimation.asset() doesn't support a package parameter, preventing Rive animations from being stored in reusable packages shared across projects.

Proposed Solution

Add a package parameter to match Flutter's convention:

RiveAnimation.asset(
  'animations/my_animation.riv',
  package: 'my_package',
)

Context

This pattern is standard across Flutter's asset APIs:

// Image
Image.asset('path', package: 'my_package')

// SvgPicture
SvgPicture.asset('path', package: 'my_package')

Benefit

Enables sharing Rive animations across multiple projects via packages, improving code reusability.

Note

I know that you’re deprecating RiveAnimation.asset() in version 0.14. In v0.14, it will look something like this:

 late final fileLoader = FileLoader.fromAsset(
        'animations/my_animation.riv',
        riveFactory: Factory.rive,
        package: 'my_package'
   );

[HayesGordon]

Thanks for the suggestion. Please note that we're migrating to new major release, where we can add support for this feature request. See the migration guide: https://rive.app/docs/runtimes/flutter/migration-guide

[eli1stark]

@HayesGordon Thank you so much for your reply! Do you have a rough estimate of when v0.14 will be released as a stable version? We want to use vector feathering for new animations and are wondering whether we should go ahead and create animations with it, hoping the stable release will be in November, or make animations without it because the release might take longer than expected.