This is basically what the community is already doing. This is the package I've been using in Flame and its license (https://pub.dev/packages/flame_spine).

"License

The code and all associated assets of the flame_spine package is distributed under the MIT License (see the LICENSE file). HOWEVER, as flame_spine includes Spine Runtime libraries, your use of flame_spine in your games or other products is also subject to the terms and conditions of the Spine Runtime License Agreement (see the LICENSE file).

In particular, in order to use flame_spine you are required to obtain a valid Spine Editor License."