feat: created sling-short.dart

lib/game/components/sling-shot.dart

@@ -0,0 +1,9 @@
+import 'package:flame_forge2d/flame_forge2d.dart';
+
+class SlingShot extends BodyComponent {
+  @override
+  Body createBody() {
+    // TODO: implement createBody
+    throw UnimplementedError();
+  }
+}