[TASK] Require doctrine/dbal 2.12.0

This is a pre-cursor for PHP 8.0 support
as well as a preliminary change to ensure
a smooth upgrade path to doctrine/dbal 3.0

Used composer command

* composer req "doctrine/dbal:^2.12"

Resolves: #92981
Releases: master
Change-Id: Ibcf217d458a669e69c84fa93d4b8ba93461e84e5
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/66971


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Daniel Haupt <mail@danielhaupt.de>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Daniel Haupt <mail@danielhaupt.de>
Reviewed-by: Benni Mack <benni@typo3.org>