v0.20.0

• The notification image now comes from Home Assistant by default, as the relative path
  /api/frigate/notifications/<event>/snapshot.jpg. The phone resolves that against its own
  Home Assistant connection, so the picture arrives at home and away without any Frigate
  address being involved. Needs the Frigate integration with its notification proxy enabled.
• This replaces a footgun reported in #13: the user had entered http://ccab4aaf-frigate:5000
  — the add-on hostname, which only resolves inside Home Assistant. The phone fetches the
  image itself, so it got nothing, on the local network and off it. That is not an obvious
  failure, because the same address works perfectly in every other setting.
• The old behaviour is still available (A Frigate address I enter below), now with the
  requirement stated where it is needed: the address must be reachable from the phone.
• Verified against a real event: the proxy path returns HTTP 200, 45 KB, image/jpeg,
  without a token.