The import path is disconnected from where the build system looks for the files. Of course, the default is to use the import path as an URL, right, but nothing forces you to do that. And if you do, *you* lock yourself to the hosting you use. But that can be hardly blamed on Go.
Documentation here: https://pkg.go.dev/cmd/go#hdr-Remote_import_paths
Full example: https://github.com/rsc/swtch/blob/master/app/rsc-io/main.go
tl;dr: Serve this at your domain, update the repo-root when changing host platform for your code: <meta name="go-import" content="import-prefix vcs repo-root">. No one else has to do anything.