Fix missing stream key argument

Author: bonnieking

src/ac_training_lab/picam/device.py

@@ -260,7 +260,7 @@ def call_lambda(action, cam_name, workflow_name, privacy_status="private"):
 
     while True:
         print("Starting stream..")
-        p1, p2 = start_stream(ffmpeg_url)
+        p1, p2 = start_stream(ffmpeg_url, stream_key)
         print("Stream started")
         interrupted = False
         try: