Update links to JSON:API documentation (community based media types)

[toedter]

I had to restructure the JSON:API for Spring HATEOAS documentation, since I now publish documentation for all released versions as well as the current snapshot on the same gh-pages branch.

The new links for the (always) latest release are:
Reference Docs: https://toedter.github.io/spring-hateoas-jsonapi/release/reference/index.html
API Docs: https://toedter.github.io/spring-hateoas-jsonapi/release/api/index.html

The new links for the current snapshot version are:
Reference Docs: https://toedter.github.io/spring-hateoas-jsonapi/snapshot/reference/index.html
API Docs: https://toedter.github.io/spring-hateoas-jsonapi/snapshot/api/index.html

You could either link to the latest released version, or to both, released and snapshot.
I did not submit a pull request since it is your decision on what and how you link.

Probably a table would be nice (ignore empty header since GitHub cannot render Markdown tables without header), like

Latest Release	Reference Docs.	API Docs.
Current Snapshot	Reference Docs.	API Docs.

Thx

Kai

[gregturn]

Thanks @toedter !

[toedter]

That was quick! Thx @gregturn.