Add bindgen as a Build Dependency

First we need to declare a build-time dependency on bindgen by adding it to the [build-dependencies] section of our crate's Cargo.toml file.

Please always use the latest version of bindgen, it has the most fixes and best compatibility. At the time of writing the latest bindgen is 0.49.2, but you can always check the bindgen page of to verify the latest version if you're unsure.

bindgen = "0.49.2"