Prevent setting of the MySQL isolation

See: DOMjudge/domjudge#2848 for the explaining of the underlying issue. This affects all released DOMjudge versions.

See: DOMjudge/domjudge@792bb6c#diff-e45e45baeda1c1e73482975a664062aa56f20c03dd9d64a827aba57775bed0d3R18

Author: vmcj

docker/docker-compose.yml

@@ -11,7 +11,7 @@ services:
       - MYSQL_DATABASE=domjudge
     ports:
       - 13306:3306
-    command: --max-connections=1000 --max-allowed-packet=512M
+    command: --max-connections=1000 --max-allowed-packet=512M --innodb_snapshot_isolation=OFF
     volumes:
       - /var/lib/mysql
   domjudge: