Library API: version each eligibility check individually

Work is currently being done to version the `library-api` as a whole, but it would be nice to somehow tag individual eligibility checks (and benefits!) with a version so that web app users can be prompted to update if a check they are using is out of date OR auto-updated if there is no change to that specific check in the latest version of the library-api.

Idea: during the release of new versions of the `library-api`, we currently use the `tag-release` script to tag the repo and pom.xml with the new version. We could extend this script to diff all DMN models against their files at the previous version git tag, and if there have been changes, update a version property somewhere within the dmn model (and have that version property be accessibility somehow via the API so the web app can read it).

Pros:
- No need to manage a separate versioning system for individual checks/benefits. (use the release script and you're good to go).

Cons:
- The semantic versioning scheme would make sense at the whole API level, but not at the individual check/benefit level. For example, a minor version bump of the API might include breaking changes to one eligibility check, but not another. However, both checks would get the same version number (the new API version) even though only one changed. (perhaps this could be overcome by some sort of diff or AI summary of the change in the web app?).