Fix date select on register absence form

The prefilled date is in September, the date picker shows February.

changed milestone to %1.0a1

added part::frontend type::bug labels

changed title from Fix date select on register absence form to Fix date select: Show prefilled date

changed title from Fix date select: Show prefilled date to Fix date select on register absence form

created merge request !91 (merged) to address this issue

mentioned in merge request !91 (merged)

assigned to @hansegucker

closed with merge request !91 (merged)

mentioned in commit dad12d3e