SameSite attribute missing for form auth cookie

[Nothing4You]

Describe the bug

Cookie SonarrAuth will be soon rejected because it has the SameSite attribute set to None or an invalid value, without the secure attribute. To know more about the SameSite attribute, read https://developer.mozilla.org/docs/Web/HTTP/Headers/Set-Cookie/SameSite

To Reproduce

1. Visit sonarr instance in Firefox
2. Check browser console

Expected behavior
No warnings.

Screenshots
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Platform Information:

• OS: macOS 11
• Docker: No
• Mono: 6.12.0.122
• Browser and Version: Firefox 86.0
• Sonarr Version: 3.0.4.1132
• Sonarr Branch: phantom-develop

Trace Logs
-

Additional information
This was already reported upstream in NancyFx/Nancy#3002, however, upstream is no longer maintained as per NancyFx/Nancy#3010. There is a PR that supposedly fixes this at NancyFx/Nancy#3006, however, as the repository is archived this won't be added upstream anymore.