FreeBSD Port: mariadb upgrade missing information in UPDATING

[Niek]

Dear maintainer:

I had several servers running mariadb53-server in the past. 
While trying to upgrade ports I ran into the issue:"pkg: No packages available to upgrade matching 'mariadb53-server' have been found in the repositories"

I figured I had to replace mariadb53* ports by mariadb55* ports, but I was not informed by /usr/ports/UPDATING.
As a matter of recommended practice I always read /usr/ports/UPDATING before doing upgrades. There is no mention in /usr/ports/UPDATING of mariadb53 being replaced by mariadb55. Please start maintaining the relevant information in /usr/ports/UPDATING going forward.