This patch adds 'version' parameter to the generated XML API for
enums.
It'll require, for new additions, to add a comment with the version
that the enum value was added.
Note that the Since tag is removed from the comment as there is a
proper field for it in the XML.
Signed-off-by: Victor Toso <victortoso@redhat.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>