Squashed commits for publication

.gitignore

CITATION.CFF

CONTRIBUTING.md

LICENSE.md

README.md

examples/features.rmmd

examples/minimum.rmmd

python/LICENSE.md

python/pyproject.toml

python/src/rmmd/__init__.py

python/src/rmmd/cli.py

python/src/rmmd/update.py

python/src/rmmd/validate.py

python/test/rmmd/test_update.py

python/test/rmmd/test_update/cff/after.cff

python/test/rmmd/test_update/cff/after.rmmd

python/test/rmmd/test_update/cff/before.cff

python/test/rmmd/test_update/cff/before.rmmd

python/test/rmmd/test_update/ct_yaml/after.rmmd

python/test/rmmd/test_update/ct_yaml/after_add_part.rmmd