Before this change we used the repo with an initial uppercase `U`. However it is now canonically spelled with a lower case `u`.
This package is too old to have a go.mod but the README clearly states the desired capitalization.
In https://github.com/unknwon/goconfig/commit/4b0d4b818a95f1242556e08cbf9912d169cbade7 the
recommended capitalization was changed to lower case.
Co-authored-by: John Oxley <joxley@meta.com>
