Following https://doc.rust-lang.org/cargo/reference/specifying-dependencies.html#specifying-path-dependencies, we need a version for path dependencies
This allows using generated code from crates that do not directly depend on pyo3. E.g.: ```rust extern crate my_pyo3_wrapper; use my_pyo3_wrapper::pyo3; #[py::modinit(rust2py)] fn init_mod(py: Python, m: &PyModule) -> PyResult<()> { // ... Ok(()) }
This makes the code generatioin reusable from third party crates.