Use `AssetPath` for resources instead of `PathBuf`

[picoHz]

Currently, the resource field in Data takes Vec<PathBuf>, which means the resources are only loadable from the default asset source. Using Vec<AssetPath> would be better for supporting flexible asset loading scenarios.

bevy_fluent/src/assets/bundle.rs

Line 70 in b5829bc

resources: Vec<PathBuf>,