Pytest-playwright-visual

fix: threshold default value

chore: tag version tweak

- feat: add fail_fast option

- visual review of mismatches
- creation of snapshots on the first run
- failing on `--update-snapshots` to make users manually review images
- snapshot name argument is not required, `test_name[browser][os].png` is generated by default
- updated folder structure: `snapshots/file_name/test_name/test_name[browser][os].png`