Python-simpleconf

- 🐛 Use static import for loaders so that freezing like cx_freeze works

**Full Changelog**: https://github.com/pwwang/python-simpleconf/compare/0.5.6...0.5.7

- ✨ Add load_one() to load only one config a time with a specified loader

**Full Changelog**: https://github.com/pwwang/python-simpleconf/compare/0.5.5...0.5.6

- ⬆️ Update rtoml to v0.8

- ✨ Add `ProfileConfig.detach()`

- ✨ Allow .osenv to load all env variables

- ✨ Allow base to be None for `ProfileConfig.use_profile()`
- ✨ Add `ProfileConfig.has_profile()`