Git commits in Moodle 3.8.x by Martin Gauk

commit b1345143ea81ce3a0b3a6b2ebaaa177fcdce2ba1
Author: Martin Gauk <gauk@math.tu-berlin.de>
Date:   Fri, 17 Jan 2020 20:13:41 +0800
Tag:    v3.8.3

MDL-51694 core_grades: use transactions when deleting


commit 8d5b7fc6cd5633b8ecbf40284e8ad02e5b0c7bb8
Author: Martin Gauk <gauk@math.tu-berlin.de>
Date:   Tue, 15 Oct 2019 23:03:33 +0800
Tag:    v3.8.0-beta

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


commit 09fd8aec272f9572137d8341a399d3d76f17714f
Author: Martin Gauk <gauk@math.tu-berlin.de>
Date:   Mon, 08 Jul 2019 17:10:11 +0800
Tag:    v3.8.0-beta

MDL-58026 question: fix regrading in progress attempt