chore: don't publish MySQL port to the host to avoid conflict on CI where 2 matrix jobs are running simultaneously

Correction for 6a5dc71 commit.

Relate to #13

Author: php-coder

docker/docker-compose.yaml

@@ -15,8 +15,6 @@ services:
       - MYSQL_USER=test
       - MYSQL_PASSWORD=test
       - MYSQL_DATABASE=test
-    ports:
-      - '3306:3306'
     volumes:
       - ./categories.mysql.sql:/docker-entrypoint-initdb.d/categories.sql
     healthcheck: