DE: Wrong weekday for date

[vaedgra]

When I switch the language from default (EN) to german (DE), the days at the top switch to it's expected position (in germany the first day of the week is monday), but the days from the month itself don't move. If 1st of Jan 2023 is a sunday in EN calendar, then it's a monday in DE calendar.

Usually you can choose "the first day of the week" to switch manually between monday and sunday, but I haven't found that option in this module.