[Feat]: Upgraded Rust toolchain to support Cargo.lock files version 4

[MatthiasZepper]

Summary

Dear Marker developers and maintainer(s),

Thanks for developing Marker. I have been using your GitHub action on my open-source project for a while now and am very happy with it!

After upgrading the dependencies on my project, which means that the Cargo.lock file is now version 4, Marker unfortunately no longer lints the code. Both, in GitHub actions and locally, I get the seemingly typical error:

cargo marker

      Marker compiling lints
    Finished release [optimized] target(s) in 0.02s

      Marker linting
error: failed to parse lock file at: /Users/matthias.zepper/Documents/Coding/Rust/umi-transfer/Cargo.lock

Caused by:
  lock file version 4 requires `-Znext-lockfile-bump`

Ed Page pointed out, that that bumping the Rust version should be sufficient to solve that issue:

Lockfile v4 has been stable since Rust 1.78. We are making it the default version as of 1.83 nighties unless your MSRV is below 1.78.

I would look into

If you can bump your Rust version
Enforce a lower Rust version is used for anyone who generates the lockfile
Set package.rust-version, if applicable

Since the last release of Marker is already a while ago, I presume that even the current nightly nightly-2023-11-16 is too old to support lock files with version 4? At least I get the same error after cargo marker setup --auto-install-toolchain, which is, I believe, the latest Rust version available for marker?

I see that you have been working on #315, but encountered lots of issues in the process. Unfortunately, I fear my basic Rust skills won't be sufficient to help out with any of those, since I do not even understand the issues while reading through them - other than Marker has issues when linting particular edge cases.

Since I presume more projects are moving to newer Rust versions, I wanted to ask if you might consider releasing a newer version of Marker without those edge cases being fixed? Or are they newly introduced by the upgraded Rust dependencies?

Thanks!
Matthias