Update GitHub Actions CI

[negezor]

Hi. Thanks for the library! I want to help to actualize the library, it will be a Pull Request series. It's worth starting with CI actualization.

• update actions/checkout to v4
• replace actions-rs/cargo with using cargo directly
• replace unmaintained actions-rs/toolchain by dtolnay/rust-toolchain

Node 16 has reached its end of life, prompting us to initiate its deprecation process for GitHub Actions. Our plan is to transition all actions to run on Node 20 by Spring 2024. https://github.blog/changelog/2023-09-22-github-actions-transitioning-from-node-16-to-node-20/

[daniel7grant]

Thank you for your PR. It is very well documented, I see no issues, only change I made is removing the additional profile parameter from the toolchain installation. I'll merge this.