Tag to be used with the master branch of atlas/athena.
Update(s) since 2.0.87:
- Updated AnalysisBaseExternals to build successfully on macOS Big Sur;
* Updated to building Python 3.8.6, and updated all clients of Python to expect this version;
* Added patches on top of ROOT 6.22/02 to make it build successfully on the new OS;
- Tweaked the build of HDF5 to avoid getting error messages during the CMake configuration of AnalysisBase on CentOS 7;
- Deprecated atlas_depends_on_subdirs(...).