    Build:
    - Dependency on OpenEXR's Half implementation has been removed from the
      core library by naturalizing the implementation into openvdb::math.
      This is fully bitwise compatible, but may require switching Half
      references to math::Half.


Add release notes for removing half dependency.
Add release notes for removing half dependency.

Signed-off-by: jlait <81974a1ed0c0d66870f9fb02ff829ce3f8e53fdd@andorra.sidefx.com>
