Log Message:
py-setuptools-rust: update to 1.6.0.

## 1.6.0 (2023-04-27)
### Changed
- Prefer passing `--crate-type` option to cargo if "toolchain >= \ 
1.64". [#322](https://github.com/PyO3/setuptools-rust/pull/322)

### Fixed
- Fix a bug where rebuilding the library would cause any running processes using \ 
it to segfault. [#295](https://github.com/PyO3/setuptools-rust/pull/295)
- Fix `setup.cfg` format for compatibility with "poetry==1.4.0". \ 
[#319](https://github.com/PyO3/setuptools-rust/pull/319)