Add the SameSite config option to the cookie creation

[kingsleyh]

I needed to secure the cookie with the SameSite configuration option. This PR adds it.

example:

   Kemal::Session.config do |config|
          config.samesite = HTTP::Cookie::SameSite::Strict
      end

The value is either SameSite::Strict or SameSite::Lax as per the existing HTTP::Cookie code in Crystal - if it's left unconfigured then it defaults to nil in the same way domain works

[rdp]

Yes please! Perhaps add to documentation? Also for followers note that SameSite::None is not available till crystal > 0.35.1

[sdogruyol]

@kingsleyh thanks for this 🙏 Is there any chance you could rebase / update this?

[kingsleyh]

Wow so long ago hah

[sdogruyol]

Gonna take over this PR 👍

[sdogruyol]

Closing in favor of #96 . Thanks @kingsleyh 🙏