Changing `package.publish` requires regenerating `target/cargo-rail`

[Twey]

After #7 cargo rail release check --all will skip those marked publish = false. However, adding publish = false to a crate after cargo rail release check --all has already been run will continue to try to check the crate until I rm target/cargo-rail/metadata.json. It would be nice if the relevant part of metadata.json were automatically recomputed.

[loadingalias]

Yeah, that's a clear invalidation issue. I'll knock this out tonight. I'm sorry, I should have thought about it. Thanks for the feedback. I'll push the fix in a few hours, hopefully... definitely this evening (EST).