chore: Upgrade to syn 2.0

[audunhalland]

No description provided.

[mmastrac]

Thank you, I'll push a new version with a minor bump.

[Kixunil]

Hey, from my understanding, this didn't change the API so bumping minor version wasn't really needed. Not a big deal I guess just something to be aware of in the future. Cool crate, BTW!

[mmastrac]

Technically true from a strict semver read, but it makes it slightly easier for people to select which version they want based on the minor since it's still a 0.x project as some folks prefer not to have two major version lines of syn in their trees.

[Kixunil]

That's still possible using Cargo.lock and that's what should be used (and I use it). Doing it via Cargo.toml makes the experience strictly worse because e.g. some other crate might forget to use ranged version and then it forces specific version on people.

[mmastrac]

In this case it doesn't hurt anything to also bump the minor because it's still 0.x, but thanks for your feedback.