Fail build if publishing a non-snapshot version with snapshot references

[shakuzen]

This is a follow-up to #3738 to ensure we don't inadvertently cause the same issue again. I'm a bit surprised such a check is not already performed somewhere along the release process, but it's possible this slipped through because it was an optional dependency that was a snapshot. This should not affect consuming the artifact without the snapshot dependency, but nonetheless, we should not publish a non-snapshot version referencing snapshot versions.