Document location of snapshot builds

I'm trying to get JSON-B updated to use the Jakarta namespace, but before I do that I wanted to start depending on the JSON-P snapshots in the jakarta namespace. Are the current snapshot builds available anywhere? If so, can that please be documented in the README?

Start by checking the repository README and its existing build or dependency documentation for references to JSON-P snapshot artifacts and the Jakarta namespace. Confirm where the current snapshots can be obtained, then document that location and usage in the README. Done means a contributor updating JSON-B can find the snapshot repository information without needing to ask in an issue.

Written by the indexing model from the issue text.