For now the entries are in no particular order. Before the release we
should have a final pass over this document and order them from most
impactful to least impactful. We might even create sections, a table of
contents, etc.
In the meantime, each PR should add an entry about it changes.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>