Update tutorial/2_sprite_animations_gestures/README.md (#805)

* Update tutorial/2_sprite_animations_gestures/README.md

Removed the premature usage of the TapDetector mixin, which is addressed later in the tutorial.

* Update CHANGELOG.md

Added change to the changelog.

packages/flame/CHANGELOG.md

@@ -12,6 +12,7 @@
  - Fix Text Rendering not working properly
  - Add more useful methods to the IsometricTileMap component
  - Add Hoverables
+ - Brief semantic update to second tutorial.
 
 ## [1.0.0-rc10]
  - Updated tutorial documentation to indicate use of new version

tutorials/2_sprite_animations_gestures/README.md

@@ -43,7 +43,7 @@ void main() {
   runApp(GameWidget(game: myGame));
 }
 
-class MyGame extends Game with TapDetector {
+class MyGame extends Game {
 
   @override
   void update(double dt) {