Support SameSite cookie

[ckifer]

Issue # (if available): #47

Description of changes:

• Support SameSite directive similar to #41
  • Add type for SameSite
  • Set SameSite using existing pattern
  • Unit test for addition and for incorrect value validation

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[ckifer]

@borisfba @jeandek any chance this gets merged soon? Thanks :)

[borisfba]

Please also update the readme with a new configuration parameter

[ckifer]

Hey @borisfba. Thanks for the review! Made documentation fixes/additions, and made sameSite optional!

Not sure if I agree on the use of an enum here, if my solution doesn't satisfy your concern I will refactor to an enum (the difference is nit, happy to use an enum). I want to avoid having to export the SameSite enum for use by consumers if possible. This way a user can just specify one of the union type values and be on their way without a new import.

Defined the allowed values directly below the union type and added a unit test as a mitigation.