Git commits in Moodle 3.11.x by Shintaro Fujiwara

commit e271fd3a796dba2bbd206a3682a41e9c260bf023
Author: Shintaro Fujiwara <shintaro.fujiwara@gmail.com>
Date:   Fri, 26 Mar 2021 09:35:51 +0800
Tag:    v3.11.0-beta

MDL-69304 gradeimport_csv: Validate if the user id is numerical.