Convert demonstration video to a much larger and less smooth animated gif because GitHub is stuck in 1995 when html5 video wasn't a thing yet

Author: daprice

README.md

@@ -7,7 +7,7 @@
 
 A slider control designed to be easy to grab and use because it can be dragged or tapped from anywhere along its track, similar to the sliders in Control Center and HomeKit.
 
-<video src="Screenshots/in_use.mp4" width="363" height="358" controls playsinline preload></video>
+<img src="Screenshots/in_use.gif" alt="Animation of TactileSliders in various orientations being clicked and dragged in the iOS simulator, followed by a transition from light to dark appearance" width="363" height="358" />
 
 ## Features