message: changelog: add brief explanation of shared_ptr removal
diff: @@ -29,6 +29,8 @@ The Axom project release numbers follow [Semantic Versioning](http://semver.org/
  from the `LuaReader` class
  - Inlet: Switched accessor interface to match that of the STL with operator[] and
  T get<T>()
  +- Inlet: `std::shared_ptr<T>` has been replaced with `T&` in non-owning contexts
  + and `std::unique_ptr<T>` in owning contexts
  ## [Version 0.4.0] - Release date 2020-09-22
  