metadata-crates-io-testing 0.0.4

Just testing what fields in a Cargo.toml can be updated after a crate has been uploaded.

The Rust book touches on this but doesn't go in too deeply about specifics.

• name: Kinda, actually creates a new crate
• version: Yes, obviously
• authors: No, according to Rust book. Changing doesn't seem to throw an error
• edition: Yes
• rust-version: ?
• description: ?
• documentation: ?
• readme: ?
• homepage: ?
• repository: ?
• license/license-file: ?
• keywords: ?
• categories: Probably not?