starting from 2019-05-01, which has been announced officially.

This fills the provisional slot acknowledged at
cacbb0fa.

Change-Id: Ifb12e6afaad4c66d455f664b46ec946e80324e87
Reviewed-on: https://gerrit.libreoffice.org/70028
Tested-by: Jenkins
Reviewed-by: Eike Rathke <erack@redhat.com>