Git commits in Moodle 3.8.x by Stephen Vickers

commit c84b8e77f1894f7998a2a93309f45b9a40c17a89
Author: Stephen Vickers <stephen@spvsoftwareproducts.com>
Date:   Wed, 26 Feb 2020 05:14:24 +0800
Tag:    v3.8.3

MDL-68049 mod_lti: Fix link-level memberships service