data type presentation concerning ods/openoffice calc files

[bernd972]

Basically the same issue as mentioned here:
#31

just that I work with openoffice cal, therefor ods files. (and not libreoffice as in the case mentioned there)
and any Datetime.date object saved to the ods file
is saved as a number, not as a proper date.

for example, if I have 25.03.2021 as a datetime.date object in the code and I try to save it as a cell content in the ods file,
it will be saved as 45133 in the openoffice calc file.

for information, I use windows 10.
I have already tried updating via pip install --upgrade pyexcel-ods3 but there seems to be no newer version availlable.