Unfortunately, most projects have moved to go.mod -- GOPATH and git submodules would have been better.
As a result, someone is using the retract feature here:

https://github.com/u-root/u-root/blob/793a1c12ac7f849185ec7dc927cf8ae9e5ad7bc4/go.mod#L71

This breaks the builds for anyone using this project. See here:

Please upgrade your deps.

Thanks!