Consider tagging module "go"? #56
Description
I found that go packages, say github.com/cncf/xds/go/udpa/annotations, are placed in submodule github.com/cncf/xds/go.
However, it seems that module github.com/cncf/xds/go is not tagged. According to Go Modules wiki, submodule should be tagged like relative-path-to-root/vX.X.X.
At now, when trying to import package github.com/cncf/xds/go/udpa/annotations, downstream would depends on pseudo-version of module github.com/cncf/xds/go.
github.com/cncf/xds/go v0.0.0-20211001041855-01bcc9b48dfe
I think it is not very readable and difficult to upgrade. This is not conductive to version control either.
So, I propose whether it is possible to tag submodule properly to better support go users. For example, go/v0.0.1, go/v1.0.0etc, so that other project can use tag to import this module in go.mod.