Upgrade the Rust Toolchain

bevy_lint matches nightly Rust versions with clippy_utils. A new version of clippy_utils is released with each version of Rust, which bevy_lint should keep up to date with.

1. Go to clippy_utils’s page on crates.io and find the nightly toolchain it requires. For example:

   This crate is only guaranteed to build with this nightly toolchain:

   nightly-2025-01-09
   

2. Change the channel field in rust-toolchain.toml to the version specified by clippy_utils.

3. Replace the toolchain version for the latest -dev version in the compatibility table.

   • Don’t replace the toolchain version in other parts of the docs, as they should use the latest stable toolchain and not the latest development toolchain.

4. Increase the version of clippy_utils in Cargo.toml to the latest version.

Once you’ve finished upgrading the Rust toolchain and clippy_utils, there are a few extra steps that can verify bevy_lint still functions the same.

1. Read over the release notes for potentially breaking changes.

2. Skim through diff.rs for clippy_utils to see if anything the linter uses may have changed.

   • clippy_utils doesn’t provide a user-facing changelog, unfortunately. You may find the Git history useful, though!

3. Verify you’ve installed the latest pinned Rust toolchain. If you use Rustup, it should be automatically installed the first time you run rustc or cargo in the workspace.

   rustc --version
   

4. Test that the linter still compiles and passes all tests.

   cargo clean
   cargo build
   cargo test
   

5. After opening the pull request, verify that the linter-action.yml workflow passes in CI.