Can't set sameSite

[Munter]

Version: cookie-store@4.0.0-next.0

The type definition of CookieListItem has a sameSite property that must be a cookieSameSite enum and does not allow strings. But this enum is not exported, so it's not possible to set sameSite in an intuitive way

[markcellus]

Thanks for filing @Munter!

cc'ing: @keithamus @koddsson for the best way to handle this in the next branch.