fixup! openvidu-browser: Stream.typeOfVideo backwards compatibility fix

Add a TODO marker to remember that we have to change this when a
breaking-change release is done.

openvidu-browser/src/OpenVidu/Stream.ts

@@ -118,7 +118,7 @@ export class Stream {
      *
      * If [[hasVideo]] is false, this property is undefined
      */
-    typeOfVideo?: keyof typeof TypeOfVideo;
+    typeOfVideo?: keyof typeof TypeOfVideo; // TODO: Change this type to enum TypeOfVideo on the next breaking-change release
 
     /**
      * StreamManager object ([[Publisher]] or [[Subscriber]]) in charge of displaying this stream in the DOM