Update proc-macro-crate to 2.0, cargo_toml to 0.16, and MSRV to 1.66.1

[oeb25]

This indirectly bumps toml_edit to v0.20.2.

Personally, this would be useful for reducing the number of versions of toml_edit we are building in our project.

[oeb25]

I see that proc-macro-crate has rust-version = "1.66.0", while num_enum has rust-version = "1.56.0" which results in the MSRV build failing, as also shown by the CI job.

It's up to you whether or not you want to bump the MSRV. I understand if you want to keep it at 1.56.0!

[oeb25]

Another bump, if you want to go ahead with this, would be cargo_toml, which is at v0.13.3 while the latest is at v0.16.3 and also depends on toml_edit v0.22.2 indirectly, minimizing the versions of toml depended on by this crate.

[oeb25]

Alright! Specifying version ranges for proc-macro-crate and cargo_toml works for the existing Cargo.toml.msrv and Rust 1.56.0. And for the latest Rust version, there's only one version of toml_edit depended upon!

[illicitonion]

Looks great, thanks so much!

[illicitonion]

This was published as 0.7.1 - thanks for the contribution!

[oeb25]

Thank you! 🎉