Cargo: include README and LICENSE files in published crates

[decathorpe]

The original change to exclude those files was probably well-intentioned, but the MIT license terms require that the license text is shipped with any redistributed sources (like those published to crates.io, or those shipped as part of linux distro packages), see - for example - the "Conditions" on the MIT entry on https://choosealicense.com.

Including the README file doesn't hurt either, but at least the LICENCE file really should be included in published crates.

[ankane]

Thanks @decathorpe - I came to submit the same thing (for the license specifically).

Edit: fwiw, for other users who need this, you can fork, apply the change, and patch the crate in Cargo.toml:

[patch.crates-io]
number_prefix = { git = "https://github.com/your-name/rust-number-prefix" }

[decathorpe]

FYI, I now "officially" forked number_prefix, made some cleanups (including this PR), and published it as https://crates.io/crates/unit-prefix