gitweb: rss/atom change published/updated date to committer date
The author date is used for published/updated date in the rss/atom
feed stream. Change it to the committer date that reflects the
"published/updated" definition better and makes rss/atom feeds more
linear. Gitlab/Github rss/atom feeds use the committer date.
Additionally, to be consistent, also use the committer date to
determine the date of the last commit to send in the feed
instead of the author date.
Signed-off-by: Jesús Ariel Cabello Mateos <080ariel@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>