Update simulcast

RTMP target. The stream_key may be included in the url.

RTMP stream key. This may be left empty if the stream_key is in the url.

SRT target. This should be the full SRT url to simulcast to, including any parameters that may be included (e.g. streamid, passphrase and latency).

RTMP target. The stream_key may be included in the url.

RTMP stream key. This may be left empty if the stream_key is in the url.

SRT target. This should be the full SRT url to simulcast to, including any parameters that may be included (e.g. streamid, passphrase and latency).