ankiconnect-22.2.19.0

Explicitly allow requests from public websites via new header (#302)

- Chrome now enforces that servers on private networks explicitly
  grant access to public websites using a new header
  "Access-Control-Allow-Private-Network" that should be sent in
  responses to preflight OPTIONS requests.
- This change implements special handling for OPTIONS requests by
  sending all the existing CORS headers along with the new
  Access-Control-Allow-Private-Network header if private network
  access is being requested.
- See https://developer.chrome.com/blog/private-network-access-preflight/
  for more info.