mail-templates: reflow text to 72 characters
From https://pagure.io/releng/pull-request/11272#comment-183297:
> Ideally, mail is under 72 or so columns, to allow for others to
> quote it and still stay less than 80 columns.
Signed-off-by: Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl>