Add support for YYYY and YYYY-MM as date formats
They are allowed by ISO8601, via schema.org, via codemeta; but not by XML Schema's date format.
Depends on !313 (closed).
Migrated from D7319 (view on Phabricator)
Staging instance, all changes can be removed at any time
They are allowed by ISO8601, via schema.org, via codemeta; but not by XML Schema's date format.
Depends on !313 (closed).
Migrated from D7319 (view on Phabricator)