[BUG] - `actions-rs/cargo` is unmaintained and must be replaced

[LeoniePhiline]

Description

actions-rs/cargo is unmaintained and must be replaced.

The respository has been set to read-only.

It must be replaced, as CI, run by actions-rs/cargo@v1, fails with outdated rustc command line options:

error: failed to run `rustc` to learn about target-specific information

Caused by:
  process didn't exit successfully: `/home/runner/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/rustc - --crate-name ___ --print=file-names -Zprofile -Ccodegen-units=1 -Cinline-threshold=0 -Clink-dead-code -Coverflow-checks=off -Cpanic=abort -Zpanic_abort_tests --crate-type bin --crate-type rlib --crate-type dylib --crate-type cdylib --crate-type staticlib --crate-type proc-macro --print=sysroot --print=split-debuginfo --print=crate-name --print=cfg` (exit status: 1)
  --- stderr
  warning: the `-Cinline-threshold` flag is deprecated and does nothing (consider using `-Cllvm-args=--inline-threshold=...`)

  error: unknown unstable option: `profile`

Steps to reproduce

1. Check https://github.com/actions-rs/cargo and find it being archived.
2. Check https://github.com/veeso/ssh2-config/actions/runs/11957708622/job/33335511680?pr=15 and see CI failing, as actions-rs/cargo uses outdated rustc CLI options.

Expected behaviour

CI works, CI dependencies are well maintained.

Environment

• Github Actions as configured in this project.

Additional information

This is a blocker for #15.

[LeoniePhiline]

Consider switching to dtolnay/rust-toolchain.

See also:

• https://github.com/dtolnay/rust-toolchain
• https://www.reddit.com/r/rust/comments/vyx4oj/actionsrs_organization_became_unmaintained/
• https://github.com/rust-lang/regex/pull/883