NOTE: ROVER should be installed from PyPI: https://pypi.org/project/rover/, usually via
pip. Do not install ROVER from these downloads.
- Remove Python 2 support, ROVER is now only supported on Python 3.8 or later
- Remove leap second file handling, now unnecessary
- Convert setup.py to pyproject.toml for modern packaging support
- Fix robot tests and convert nose tests to pytest
- Convert to new EarthScope branding and theme on documentation site