Setup Benchmark Go v1.0.3

Organization migration release.

• publish the action from xgo-dev/setup-benchmark-go-action
• update documentation and self-benchmark metadata to the organization repository
• keep the repository self-test action on a local relative path
• pin the reusable publisher workflow to xgo-dev/setup-benchmark-go-action/publish@v1.0.3

The action implementation and bundled runtime are unchanged from v1.0.2.