Git merges in Moodle 3.8.x by AMOS bot

commit ef5abe6f1a639fffdc9f0b6992db6b9963d81768
Author: AMOS bot <amos@moodle.org>
Date:   Sat, 12 Dec 2020 08:07:50 +0800
Tag:    v3.8.7

Merge branch 'MOODLE_38_STABLE' into install_38_STABLE