v0.7.0

• Docs: a domain claim takes an optional purpose (email, site or
  both, default email), and the domain the claim produces is created with
  that purpose; every claim response carries purpose. The parameter passes
  through the existing claim call; only the doc comments change here. Needs the
  API deployed with this change.

---

Released from mailtea-app/mailtea@1ea0e1b.