[korbindeman]

This upgrades bevy_erosion_filter from Bevy 0.19 to Bevy 0.20 and prepares crate release 0.3.0. It does not publish to crates.io or create tags/releases.

Version bumps

• Crate: 0.2.0 → 0.3.0
• bevy: 0.19 → 0.20
• glam: 0.32 → 0.33 (Bevy 0.20 uses glam 0.33)
• bevy_egui: 0.40.1 → 0.43
• MSRV: Rust 1.89 → 1.97 (matches Bevy 0.20's rust-version)

Shader import path (checked against Bevy 0.20 source)

I did not take the migration guide's WESL / #define_import_path wording on faith. In the v0.20.0 tag:

• #define_import_path is gone. Shader::from_wgsl no longer runs naga_oil preprocessing, and a repo search for define_import_path returns nothing.
• WESL import paths come from the asset path. For embedded://bevy_foo/bar.wesl, Bevy registers bevy_foo::bar.
• load_shader_library!(app, "erosion.wesl") from src/lib.rs therefore embeds embedded://bevy_erosion_filter/erosion.wesl and keeps the public import bevy_erosion_filter::erosion.

The library shader moved to src/erosion.wesl (still plain WGSL with no preprocessor, so EROSION_WGSL remains usable with raw wgpu). The terrain demo is now WESL:

• #import bevy_pbr::… → import bevy_pbr::render::…;
• #{MATERIAL_BIND_GROUP} → constants::MATERIAL_BIND_GROUP

Docs

• README Bevy compatibility table: 0.1 → 0.18, 0.2 → 0.19, 0.3 → 0.20
• CHANGELOG 0.3.0 entry

Verification

• cargo build --all-targets
• cargo test --all-targets (5 CPU tests passed; terrain_demo compiles)
• cargo clippy --all-targets -- -D warnings
• cargo fmt --check
• cargo package --allow-dirty

I could not run the terrain demo in a GUI here; CI should still compile it as part of --all-targets.