IGListAdapterDelegate needs Swift name of ListAdapterDelegate (#1116)

Summary:
## Changes in this pull request

Add Swift name annotation `ListAdapterDelegate` to `IGListAdapterDelegate`. The breaking change is written in the `CHANGELOG.md` for the `4.0.0` release

Issue fixed: https://github.com/Instagram/IGListKit/issues/1115

### Checklist

- [x] All tests pass. Demo project builds and runs.
- [x] I added tests, an experiment, or detailed why my change isn't tested.
- [x] I added an entry to the `CHANGELOG.md` for any breaking changes, enhancements, or bug fixes.
- [x] I have reviewed the [contributing guide](https://github.com/Instagram/IGListKit/blob/master/.github/CONTRIBUTING.md)
Pull Request resolved: https://github.com/Instagram/IGListKit/pull/1116

Reviewed By: bdotdub

Differential Revision: D18278551

Pulled By: iperry90

fbshipit-source-id: db9d1910fc4be7ffa723ee291a9c65db0fd217c0

CHANGELOG.md

@@ -6,6 +6,8 @@ The changelog for `IGListKit`. Also see the [releases](https://github.com/instag
 -----
 ### Breaking Changes
 
+- Added Swift annotation name to `IGListAdapterDelegate` which removes `IG` prefix. The new name for Swift clients is `ListAdapterDelegate`. [Andrea Antonioni](https://github.com/andreaantonioni)[(#1116)](https://github.com/Instagram/IGListKit/pull/1116)
+
 - Remove support for iOS 8
 
 - `IGListKit` has been split into `IGListKit` and `IGListDiffKit` for Xcode and Carthage builds. Cocoapods continues to use an all-inclusive `IGListKit` podspec. [Nate Stedman](https://github.com/natestedman) ([#1377])(https://github.com/Instagram/IGListKit/pull/1377)

Source/IGListKit/IGListAdapterDelegate.h

@@ -14,6 +14,7 @@ NS_ASSUME_NONNULL_BEGIN
 /**
  Conform to `IGListAdapterDelegate` to receive display events for objects in a list.
  */
+NS_SWIFT_NAME(ListAdapterDelegate)
 @protocol IGListAdapterDelegate <NSObject>
 
 /**