Update crossbeam-utils requirement from 0.7.2 to 0.8.1 (#959)

Updates the requirements on [crossbeam-utils](https://github.com/crossbeam-rs/crossbeam) to permit the latest version.
- [Release notes](https://github.com/crossbeam-rs/crossbeam/releases)
- [Changelog](https://github.com/crossbeam-rs/crossbeam/blob/master/CHANGELOG.md)
- [Commits](https://github.com/crossbeam-rs/crossbeam/compare/crossbeam-0.7.2...crossbeam-utils-0.8.1)

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Carter Anderson <mcanders1@gmail.com>

crates/bevy_wgpu/Cargo.toml

@@ -32,5 +32,5 @@ bevy_utils = { path = "../bevy_utils", version = "0.4.0" }
 wgpu = "0.7"
 futures-lite = "1.4.0"
 crossbeam-channel = "0.5.0"
-crossbeam-utils = "0.7.2"
+crossbeam-utils = "0.8.1"
 parking_lot = "0.11.0"