Add a `readme_renderer` check to `build.yml`

[siddacious]

I ran into an issue with Adafruit_CircuitPython_ICM20649 :
adafruit/Adafruit_CircuitPython_ICM20X#1
An issue with the parsing of the README.rst was preventing it from getting uploaded to PyPi. The symptom was a failing "Release Actions" -> "upload-pypi" job with this error:

The included URL pointed me to docs that lead me to the 'readme_parser' module that PyPi users. I was able to test with:

pip install --user --upgrade setuptools wheel twine readme_renderer
python setup.py sdist
python setup.py bdist_wheel --universal
twine check dist/*

[evaherrada]

Might also need to install testresources, I did when I installed this

[makermelissa]

It seems like this step conflicts with the release.yml in that it checks for a file named setup.py to determine if it should upload to PyPI, but without setup.py here it fails build.yml.

[evaherrada]

@makermelissa oh yeah, I completely overlooked that. I'll make a pr wtih a fix soon.