downloads rest api - release status on individual releases missing

Top level https://downloads.mariadb.org/rest-api/mariadb/ contains the release status of the major branches.

Navigating to a lower level like https://downloads.mariadb.org/rest-api/mariadb/10.2.31/ fails to include the release status of the actual version.

On something like https://downloads.mariadb.org/rest-api/mariadb/10.2.2/ to work out the release status you'd need to parse this out of the `release_name`.

REST should provide a single item per field. Preferably matching the same name as the major version API.