- toml provider is changed from [`pytoml`](https://pypi.org/project/pytoml/) (deprecated) to [`toml`](https://pypi.org/project/toml/)
1.4
- support pip v20.0.2 (for real this time)
1.3
- support pip v20
1.2
- Improved handling of non-trivial [environment markers](https://www.python.org/dev/peps/pep-0508/#environment-markers).
1.1
- Add support for basic auth specified directly in `--index-url` and/or `--extra-index-url`, contributed by ddelange
1.0
- support pip 19.3 (pip keep breaking us by twiddling with their messages, this time it was https://github.com/pypa/pip/commit/59e2b6f6808ba387464c76675a1d0b9790f29a9a) - now cleans up temporary files better