fix: exclude ignored files using cargo package list

[lutaok]

Hello,
Opening this PR to fix #721

Changes:

• used cargo package --list to get files from local and registry packages
• ignored Cargo.toml.orig, .cargo_vcs_info.json and Cargo.lock files
• Removed directory traversing walker while checking diffs

Thanks for the guidance @MarcoIeni !

[MarcoIeni]

This is such a great improvement. I tried running release-plz in the tokio repository after this change, and I can see that the result looks much better because release-plz ignores the fuzz directory, which is indeed not published to crates.io (but still is a subdirectory of the tokio crate). 🎉

Thanks for working on this 🙏
I just did a couple of changes to refactor and a few minor fixes.