Git commits in Moodle x.x.x by Justin Merrill

commit 52a84caaaa12c3b313b264710e0bba3db9765cf2
Author: Justin Merrill <Justin.Merrill@ethinkeducation.com>
Date:   Wed, 07 Oct 2020 21:03:08 +0800
Tag:    v3.10.0-beta

MDL-69760 core: add mdl_event index for assign adhoc tasks