Git commits in Moodle 3.10.3 by Brendan Heywood

commit 6b7850290b6ad39be7087687463a61fa782f255e
Author: Brendan Heywood <brendan@catalyst-au.net>
Date:   Wed, 17 Mar 2021 14:37:29 +0800
Tag:    v3.10.3

MDL-71068 login: Fix edge cases with $CFG->protectusernames