message: Add redirect from changelog to readme.
diff: # Change Log
  -All notable changes to the "lean" extension will be documented in this file.
  -Check [Keep a Changelog](http://keepachangelog.com/) for recommendations on how to structure this file.
  -
  -## [Unreleased]
  -- Initial release
  \ No newline at end of file
  +Changes are listed in the [./README.md](README).
  