mariadb: Update to the latest version 10.4.26
Keeping the major version, bumping just a minor version. It includes
various bug fixes and security fixes. For details, see:
* https://mariadb.com/kb/en/mariadb-10426-release-notes/
* https://mariadb.com/kb/en/mariadb-10425-release-notes/
* https://mariadb.com/kb/en/mariadb-10424-release-notes/
* https://mariadb.com/kb/en/mariadb-10423-release-notes/
While at it, also switching to AUTORELEASE and refreshing patches.
Signed-off-by: Michal Hrusecky <michal@hrusecky.net>