Fails with new `Cargo.lock` format

[otavio]

cargo has enabled the new format by default[1] and this causes the cbindgen to fail to parse the dependencies.

1. Turn the new lock file format on by default rust-lang/cargo#7579

It fails at https://github.com/eqrion/cbindgen/blob/master/src/bindgen/cargo/cargo.rs#L125 as the new format does not has the version annotated on the same line.

[emilio]

Thanks for filing, will take a look.

[est31]

One could switch to the cargo crate to parse the Cargo.lock format, but this would hopelessly inflate the number of dependencies as it would include everything cargo is depending on. Ideally, one could ask the cargo maintainers to extract the Cargo.lock parsing code into a separate crate and to then use that.

[emilio]

I had to catch up with the lockfile changes, but I think #438 should be enough.

[otavio]

I had to catch up with the lockfile changes, but I think #438 should be enough.

I tested the PR and it worked just fine. Thanks for looking at it.