[bug#64035] [PATH] fix a bug on importing go packages.

[Elbek]

Hello.

This patch addresses the issue https://issues.guix.gnu.org/63001

Currently "guix import go ..." looks to the repository depending on the version 
of a package.

For example, if package version is $1.11.0$, the importer tries to look to the 
repository's tag named v1.11.0,
but some packages are using tags that are prefixed by the module name.

For example, the package cloud.google.com/go/workflows use the tag 
workflows/v1.11.0

This patch changes go importer, such that it looks to the module-name prefixed 
tags if they exists, and behaves as before otherwise.