fix dataset_id error on Windows

[kaixin96]

Description

Changed how to retrieve dataset_id from the path when listing local datasets. Previously, a string returned by os.path.join will be appended to the dataset_ids. However, this would break on Windows as Windows paths use backslash. Such dataset_id doesn't match the required pattern. This fix wraps the path string with pathlib.PurePath and converts it to posix path.

Fixes #238.

Type of change

• Bug fix (non-breaking change which fixes an issue)

Screenshots

Before

After

Checklist:

• I have run the pre-commit checks with pre-commit run --all-files (see CONTRIBUTING.md instructions to set it up)
• I have run pytest -v and no errors are present.
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I solved any possible warnings that pytest -v has generated that are related to my code to the best of my knowledge.
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[younik]

LGTM, thanks!