Twine is having some issues with markdown.  Add text\markdown to setup.py, remove triple back ticks from README.md.
Similar to what we had to do in
@@ -38,6 +38,7 @@ setup(
description='Tools to interface with Radiance',
long_description=long_description,
+ long_description_content_type="text/markdown",
# The project's main homepage.
url='https://github.com/NREL/bifacial_radiance',
