Add support for the Account Link resource

[remi-stripe]

cc @stripe/api-libraries
r? @brandur-stripe

[brandur-stripe]

LGTM!

[ob-stripe]

Released as 4.3.0.

[benissimo]

Where can we find documentation about AccountLink? I've seen mention of it in a "Hosted Verification Beta" PDF but can't find any mention of AccountLink in Stripe's online docs.

[ob-stripe]

@benissimo Hosted Verification is still in private beta, so you need to be logged into a Stripe account that has access to the beta in order to be able to view the documentation on Stripe's site.

[benissimo]

Thanks @ob-stripe, I'll ask our contacts to enable the beta.

[benissimo]

@ob-stripe It turns out we were already enabled for the beta but that's not sufficient. We had to set values for branding (https://dashboard.stripe.com/account/applications/settings). Once we did that, the API docs began mentioning AccountLink. Without that, they skipped any mention of it. Noting this here in case it helps anyone who runs into the same issue.