[ios] Updated changelog for map thread removal

platform/ios/CHANGELOG.md

@@ -12,6 +12,7 @@ Mapbox welcomes participation and contributions from everyone.  Please read [CON
 - Setting the `image` property of an MGLAnnotationImage to `nil` resets it to the default red pin image and reclaims resources that can be used to customize additional annotations. ([#3835](https://github.com/mapbox/mapbox-gl-native/pull/3835))
 - Fixed an issue preventing KVO change notifications from being generated on MGLMapView’s `userTrackingMode` key path when `-setUserTrackingMode:animated:` is called. ([#4724](https://github.com/mapbox/mapbox-gl-native/pull/4724))
 - Fixed a hang that could occur if the host application attempts to set user defaults on a background queue. ([#4745](https://github.com/mapbox/mapbox-gl-native/pull/4745))
+- Rendering now occurs on the main thread, fixing a hang when calling `-[MGLMapView styleURL]` before the map view has fully loaded or while the application is in the background. ([#2909](https://github.com/mapbox/mapbox-gl-native/pull/2909))
 - Added a `-reloadStyle:` action to MGLMapView to force a reload of the current style. ([#4728](https://github.com/mapbox/mapbox-gl-native/pull/4728))
 - A more specific user agent string is now sent with style and tile requests. ([#4012](https://github.com/mapbox/mapbox-gl-native/pull/4012))
 - Mapbox Telemetry is automatically disabled while the host application is running in the iOS Simulator. ([#4726](https://github.com/mapbox/mapbox-gl-native/pull/4726))