AWS SDK for Android 2.15.2

Bug Fixes

• AWS Mobile Client
  • Fix issue where MobileClient would return invalid tokens after initialization when using Hosted UI.
    See issue #873 and
    issue #888
• Amazon Cognito Identity Provider
  • Use internal username for computing secret hash that is passed in challenge response. See Issue# 889 for details

Misc. Updates

• Model updates for the following services
  • Amazon Connect
  • Amazon Rekognition
  • Amazon Transcribe