incorrect SPDX v2.3 → v3.0 external references in example4-bin.json

The [example4-bin.json](https://github.com/spdx/spdx-examples/blob/35818de46f1c8c23e2384740f0e77bc5cbafac1f/software/example4/spdx3.0/example4-bin.json#L92) SPDX v3 document seems to incorrectly reference external elements from the example4-src.json document using v2.3 identifiers (`SPDXRef-lib-src`, `SPDXRef-main-src`) rather than the v3.0 identifiers (`SPDXRef-gnrtd6`, `SPDXRef-gnrtd17`).