main
modify gendiff-check.yml: remove pip install flake8
update stylish.py: use isinstance() for defenition of dict
correct tests/test_gendiff.py for lint pass
update .gitignore : add coverage.xml
Simplify package installation and uninstallation
fix README.md with simple install command
uninstall pyyaml from group dev so modify poetry.lock and pyproject.toml
modify setup.cfg: change dir in per-file-ignores