There is a new import path for the xz package used in registry/fetch.go (which you have also vendored). It is github.com/xi2/xz. The old one will cease to work at some point. Sorry for the inconvenience.
Thanks for the heads up. The dependencies are vendored in this project, so nothing will break when the old import path is removed, and this project is no longer actively maintained so I see no reason to update it.
There is a new import path for the
xz
package used inregistry/fetch.go
(which you have also vendored). It isgithub.com/xi2/xz
. The old one will cease to work at some point. Sorry for the inconvenience.