Git commits in Moodle 3.11.x by Tim Schroeder

commit 647c5ac8cd2ed21b0ba7a364709b2bb41a278695
Author: Tim Schroeder <t.schroeder@itc.rwth-aachen.de>
Date:   Tue, 03 Nov 2020 18:53:32 +0800
Tag:    v3.11.0-beta

MDL-70110 assign: fixed ws get_submissions for groups