Add compiler flag to switch between ros2 and ros1 versions

Co-authored-by jannick-schroeer <jannick.schroer@gmail.com>
Co-authored-by zhaona99 <guozhaona99@gmail.com>

Author: Soldann

Assets/Components/VRStreamer/Scripts/Streamer.cs

@@ -52,7 +52,11 @@ void Start()
 
         _camera.CopyFrom(Camera.main);
 
+#if ROS2
         _header = new HeaderMsg(new TimeMsg(0, 0), "VR");
+#else
+        _header = new HeaderMsg(0, new TimeMsg(0, 0), "VR");
+#endif
 
         // _camera = Camera.main;
         _camera.targetTexture = _renderTexture;