v2.7.0 — arr-metadata-server by key

arr-metadata-server 0.8.1 lets its Plex provider ask for keys (AMS_PLEX_AUTH=apikey)
without shutting Plex out: Plex is given the provider's address with a key at its end,
…/plex/<key>. This release follows it: this app can now be let in by a key as well as by
its address.

Setting it up

With AMS_PLEX_AUTH=apikey on the server:

1. Under Keys & network, issue this app a key of its own, one that only reads.
2. Set it as ARR_METADATA_API_KEY. The address of the Plex panel, …/plex/<key>,
   works as ARR_METADATA_URL too, but the server's guide keeps that key for Plex alone:
   revoking it would shut both out.
3. Config › Checks says whether the server takes it.

The key travels in an X-Api-Key header, never in an address. An address carrying one is
shown with /plex/*** — in the console, the doctor and the logs — and so is a key in its
query. A key carries its own settings on the server, the language the genres come in among
them.

A server that lets callers in by address, its default, needs nothing new.

What else changes

• A refusal says which way in failed, and which setting to change: a key missing, or
  one the server does not know; an address not on its list, or a key switched off or run
  out; a key whose account is no longer active. A refusal the server did not send — from a
  reverse proxy in front of it, and the password it asks for — is now said to come from
  there, rather than blamed on the server.
• ARR_METADATA_URL and ARR_METADATA_API_KEY naming two different keys are refused, with
  the reason, by the libraries that read from ams and by the doctor.

Upgrading

Pull and restart: nothing to change.