Git commits in Moodle 3.9.7 by Juan Leyva

commit 39916b12fd357fb2c92716b0046c71bd828359ce
Author: Juan Leyva <juanleyvadelgado@gmail.com>
Date:   Wed, 31 Mar 2021 23:49:58 +0800
Tag:    v3.9.7

MDL-70863 mod_forum: Allow NULL in timecreated