ci: update checked rust-toolchain version

[robjtede]

No description provided.

[robjtede]

i'm mostly just trying to see a fresh CI run to compare for PR 26

[robjtede]

still seeing an error printed during rust install

Run Swatinem/rust-cache@v2
Error: The process '/home/runner/.cargo/bin/cargo' failed with exit code 101
    at ExecState._setResult (/home/runner/work/_actions/Swatinem/rust-cache/v2/dist/restore/index.js:7784:25)
    at ExecState.CheckComplete (/home/runner/work/_actions/Swatinem/rust-cache/v2/dist/restore/index.js:7767:18)
    at ChildProcess.<anonymous> (/home/runner/work/_actions/Swatinem/rust-cache/v2/dist/restore/index.js:7661:27)
    at ChildProcess.emit (node:events:514:28)
    at maybeClose (node:internal/child_process:1105:16)
    at ChildProcess._handle.onexit (node:internal/child_process:305:5) {
  commandFailed: {
    command: 'cargo metadata --all-features --format-version 1 --no-deps',
    stderr: '\x1B[1m\x1B[31merror\x1B[0m\x1B[1m:\x1B[0m could not find `Cargo.toml` in `/home/runner/work/setup-rust-toolchain/setup-rust-toolchain` or any parent directory\n'
  }
}

[robjtede]

oh i guess that makes sense for this repo

[robjtede]

@jonasbb i was so lost wondering where $toolchain came from when i realized that env: block was below the script so i've moved stuff around a bit to make things more clear