message: docs: update release notes with details on MFEMSidreDataCollection
diff: @@ -58,6 +58,9 @@ The Axom project release numbers follow [Semantic Versioning](http://semver.org/
  - Added [Sol] as a built-in TPL for fast and simple `C++` and `Lua` binding.
  Sol is automatically enabled when `LUA_DIR` is found.
  The version of Sol used in this release is `v2.20.6`, which requires `C++14`.
  +- Added the MFEMSidreDataCollection class for HDF5-format simulation data collection. This
  + class was adapted from MFEM's SidreDataCollection and is enabled when Axom is build with MFEM
  + *and* the `AXOM_ENABLE_MFEM_SIDRE_DATACOLLECTION` CMake option is enabled.
  ### Removed
  