With the breaking change of renaming ASNavigationController to ASDKNavigationController, we have released a new version of Texture. Please see `ThreeMigrationGuide.md` for how to handle the breaking changes in 3.1.0.
* Renames AS_EXTERN and ASViewController
To ASDK_EXTERN and ASDKViewController.
This is to avoid conflicting with AuthenticationServices in
Xcode 12
* Fix up examples and docs
* Add bit about updating ASViewController rename