feat: add rtmp support (#1009)

* feat: add rtmp support

* Update detect.py

pass tuple to source.startswith()

Co-authored-by: ryan.fu <ryan.fu@aylaasia.com>
Co-authored-by: Glenn Jocher <glenn.jocher@ultralytics.com>

README.md

@@ -77,6 +77,7 @@ $ python detect.py --source 0  # webcam
                             path/  # directory
                             path/*.jpg  # glob
                             rtsp://170.93.143.139/rtplive/470011e600ef003a004ee33696235daa  # rtsp stream
+                            rtmp://192.168.1.105/live/test  # rtmp stream
                             http://112.50.243.8/PLTV/88888888/224/3221225900/1.m3u8  # http stream
 ```