Update CHANGELOG-v3.50.md

Author: photonstorm

CHANGELOG-v3.50.md

@@ -646,6 +646,7 @@ Since v3.0.0 the Game Object `render` functions have received a parameter called
 * When running an Arcade Physics `overlap` test against a `StaticBody`, it will no longer set the `blocked` states of the dynamic body. If you are doing a collision test, they will still be set, but they're skipped for overlap-only tests. Fix #4435 (thanks @samme)
 * The `Line` Game Object will now default its width and height to 1, rather than zero. This allows you to give Line objects a physics body (although you will still need to re-adjust the center of the body manually). Fix #4596 (thanks @andrewaustin)
 * Internally, the `Quaternion` class now has 4 new private properties: `_x`, `_y`, `_z` and `_w` and 4 new getters and setters for the public versions. It also now passes most methods via `set` to allow for the onChange callback to be invoked. This does not change the public-facing API.
+* `Group` now extends `EventEmitter`, allowing you to emit custom events from within a Group.
 
 ### Bug Fixes