Make Gitlab CI compatible with MySQL 8.4

In MySQL 8.4, the mysql_native_password server-side plugin is disabled
by default. Specify the --mysql-native-password option to enable it,
until we investigate a proper migration to new authentication methods.

Author: Kevinjil

gitlab/ci/template.yml

@@ -36,7 +36,7 @@
     - /bin/true
   services:
     - name: mysql
-      command: ["--default-authentication-plugin=mysql_native_password"]
+      command: ["--mysql-native-password", "--authentication_policy=mysql_native_password"]
       alias: sqlserver
 
 .mariadb_job: