[MariaDB Packagers] MariaDB 10.2.18 release prep

Prep work for the MariaDB 10.2.18 release has begun. Expected release date is Tue 25 Sep 2018. Draft release notes and changelog: - https://mariadb.com/kb/en/mariadb-10218-release-notes/ - https://mariadb.com/kb/en/mariadb-10218-changelog/ As usual, the release notes and changelog are still in draft form at this time and will be updated prior to release. Thanks. -- Daniel Bartholomew, MariaDB Release Manager MariaDB | https://mariadb.com