- Update `__init__.py` to improve readability in path validation logic.
- Bump version number in `pyproject.toml` from 0.1.0 to 0.1.1. 🚀

The refactoring in `__init__.py` enhances code readability by assigning
the result of `x.with_suffix("")` to a variable `y`, which clarifies
repetitive use. The version bump reflects these minor, yet valuable
improvements in the project.