Current FireFox is warning and also coming soon to Chrome.
That's the warning on from test, I see the same thing on other sites.
Maybe this will help:
https://stackoverflow.com/questions/59195284/how-to-set-samesite-attribute-to-none-secure-in-rails3-1-12-and-ruby1-9-3
Both Chrome and FireFox will require this at some point this year probably. From everything I can find it's probably best to take care of this in whatever version comes out later in the summer/fall this year and I don't think it needs to be done NOW (the early June release), but probably next version.
https://blog.chromium.org/2020/05/resuming-samesite-cookie-changes-in-july.html