ruamel-yaml aftermath

[msftcangoblowm]

Production dependency strictyaml depends on ruamel-yaml

myst-parser only requires ruamel-yaml with testing dependencies installed. Which were not needed.

ruamel-yaml has non-optional dependency ruamel-yaml-clib which uses a setup.py and requires setuptools in the environment, rather than pyproject.toml specifying the build environment.

Doesn't seem that ruamel-yaml supports PyPy. So had to drop that.

Added the restriction pip<24.2. After ruamel-yaml-clib couldn't build on PyPy py310 MacOS and PyPy py310 Ubuntu. In classifiers, doesn't advertise having PyPy support.

pip<24.2 could be removed or can wait until the ruamel-yaml team addresses pypa/pip#12884 and ruamel-yaml#521

pip<24.2 will be removed soon; known issue