Remove TCA config 'max' on inputDateTime fields
It would be a good idea to remove the 'max' config option in TcaMigration class automatically
for all renderType="inputDateTime" fields.
We've had a max=20 in core for pages.newUntil field for a while, and
this killed the db entry on storing.
Since that is a relatively hard to spot and test issue for extension
authors during upgrade, it might be the easiest solution to just have
a TcaMigration (with unit test) to remove 'max' on those fields