[feat] Generic webhook: support GET

[huyz]

Healthchecks.io and Uptime Kuma accept pushes/pings as GET requests.

But Shoutrrr only supports POST requests. Could GET be added? Even if no query parameters are supported.

[JordyEGNL]

A little late, but uptime kuma supports POST requests now, and shoutrrr can support GET

generic://status.domain.tld/api/push/randomstring?template=json

?RequestMethod=GET for GET

[piksel]

Yeah, Shoutrrr does support GET requests, but it has to be specified using the query parameter method=GET. Using RequestMethod and Method as the query paramter should work, but currently doesn't.