py-pyelftools: updated to 0.28

Version 0.28 (2022.02.03)

- Added a method for returning the index of a section by name
- Allow filtering by section types in iter_sections
- Support Android compressed rel/rela sections
- Initial support for PPC64LE
- Initial DWARF v5 support
- Fixed parsing for structures containing uids or gids in core
  dumps
- Allow filtering by segment types in iter_segments
- Add support for .note.gnu.property
- Update readelf tests to work with more recent version of
  readelf
- Add support for note GNU_PROPERTY_X86_FEATURE_1_AND

(adam)