Fix docker compose with new mariadb environment variable name (CTFd#2533)

Co-authored-by: Kevin Chung <[email protected]>

Author: d3vyce

docker-compose.yml

@@ -40,10 +40,10 @@ services:
     image: mariadb:10.11
     restart: always
     environment:
-      - MYSQL_ROOT_PASSWORD=ctfd
-      - MYSQL_USER=ctfd
-      - MYSQL_PASSWORD=ctfd
-      - MYSQL_DATABASE=ctfd
+      - MARIADB_ROOT_PASSWORD=ctfd
+      - MARIADB_USER=ctfd
+      - MARIADB_PASSWORD=ctfd
+      - MARIADB_DATABASE=ctfd
       - MARIADB_AUTO_UPGRADE=1
     volumes:
       - .data/mysql:/var/lib/mysql