"Partitioned" attribute needed for the set-cookie header

[Parbelaez]

Hello,

As many browsers are rejecting the set-cookie header when SAMESITE is set to none, it would be good if a new attribute "PARTITIONED" is created. Unless, the authentication under this set-up will be impossible in a near future. As far as I see, only Firefox is still supporting set-cookie headers without this parameter.

Would it be possible to add this in the next major release?... as well as #584 . It would be extremely helpful.

https://developers.google.com/privacy-sandbox/3pcd/chips

I am sorry, I am new to Django, so I cannot send a PR (for now). But I am willing to help in any sort of way that I can.

Thanks!