Find a way to improve/automate the process of publishing new crate versions

[GabrielMajeri]

Pull request #322 documents the way new versions of the crates in the project workspace are marked and published to crates.io. That being said, the process is manual and fairly error prone, so we could look into improving the various steps.

To begin with, we could look into using the cargo-release tool, as suggested in https://github.com/rust-osdev/uefi-rs/pull/322#pullrequestreview-829658015.

[nicholasbishop]

I just did my first release, wrote up some notes on the process here: https://github.com/rust-osdev/uefi-rs/issues/340#issuecomment-1013563793