Git commits in Moodle 3.7.3 by Martin Gauk

commit 9ccc9ec17515ed930df833ab32bd18d1c9968733
Author: Martin Gauk <gauk@math.tu-berlin.de>
Date:   Tue, 15 Oct 2019 23:03:33 +0800
Tag:    v3.7.3

MDL-66915 assign: Notify only if grade was updated in past 24 hours