Update CHANGELOG-v3.50.md

Author: photonstorm

CHANGELOG-v3.50.md

@@ -583,6 +583,7 @@ Since v3.0.0 the Game Object `render` functions have received a parameter called
 * The `Quaternion` class constructor will now default the values to `0,0,0,1` if they're not provided, making it an identity quaternion, rather than the `0,0,0,0` it was before.
 * You can now set the `ParticleEmitter.reserve` value via the emitter configuration object (thanks @vforsh)
 * Setting the `pixelArt` config option will now set `antialiasGL` to `false`, as well as `antialias`. Fix #5309 (thanks @Vegita2)
+* The `Shape` class now includes the `ComputedSize` component properties and methods directly in the class, rather than applying as a mixin. `setSize` is now flagged as being `private`, because it shouldn't be used on Shape classes, which was leading to confusion as it appeared in the public-facing API. Fix #4811 (thanks @aolsx)
 
 ### Bug Fixes