fix: handle case-sensitive export.xml

[aozsyn]

in re bug #40

[alxdrcirilo]

Hey!

Thanks for making a PR. So I tried this locally but it won't work. That's because the implementation has a small bug: Path.resolve() never raises FileNotFoundError. By default it uses strict=False, so it just returns an absolute path regardless of whether the file exists or not.

I think it would be better to use Path.exists() instead (and fallback to the capitalised Export.xml when export.xml does not exist). Maybe something like this?

path = export_dir / "export.xml"
if not path.exists():
    path = export_dir / "Export.xml"

return path.resolve()

Do you also have some time to add a test for this? If you'd like to do the entire PR by yourself, that's fine too. And if you'd like me to make a test, that's equally fine by me :)