Reporting warnings for external packages on Windows

[delsner]

I'm using go-licenses to create a conda-forge feedstock.
During the Windows build (and only on Windows), go-licenses prints warnings for most (all?) external packages, e.g.:

$ go-licenses save ./cmd/logcli --save_path ../library_licenses --ignore github.com/grafana/loki
...
W0209 18:12:36.211214    2404 library.go:163] module github.com/josharian/intern does not have dir and it's not vendored, cannot discover the license URL. Report to go-licenses developer if you see this.
W0209 18:12:36.211214    2404 library.go:163] module github.com/go-kit/kit does not have dir and it's not vendored, cannot discover the license URL. Report to go-licenses developer if you see this.
W0209 18:12:36.211214    2404 library.go:163] module github.com/spf13/afero does not have dir and it's not vendored, cannot discover the license URL. Report to go-licenses developer if you see this.
...

Therefore, I'm reporting this issue here and would appreciate any pointers on how to fix these warnings on my end.
Thank you!