Git commits in Moodle 3.9.0 by Matteo Scaramuccia

commit a8a4eac163fb7a52131f7e55a19aa1667d3bf64e
Author: Matteo Scaramuccia <moodle@matteoscaramuccia.com>
Date:   Sat, 30 Nov 2019 07:03:31 +0800
Tag:    v3.9.0-beta

MDL-67414 database: Fixed PostgreSQL 12.x support