bump: update bevy requirement from 0.7 to 0.8 (#429)

Updates the requirements on [bevy](https://github.com/bevyengine/bevy) to permit the latest version.
- [Release notes](https://github.com/bevyengine/bevy/releases)
- [Changelog](https://github.com/bevyengine/bevy/blob/main/CHANGELOG.md)
- [Commits](bevyengine/bevy@v0.7.0...v0.8.0)

---
updated-dependencies:
- dependency-name: bevy
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Bas Zalmstra <zalmstra.bas@gmail.com>

crates/mun_runtime/Cargo.toml

@@ -28,7 +28,7 @@ rustc-hash = "1.1"
 seq-macro = "0.3.0"
 
 [dev-dependencies]
-bevy = "0.7"
+bevy = "0.8"
 compiler = { version="=0.3.0", path="../mun_compiler", package = "mun_compiler" }
 criterion = "0.3"
 mlua = { package ="mlua", version="0.8", default-features = false, features=["vendored", "luajit"]  }