ModuleNotFoundError: No module named 'pkg_resources'

We have a runtime dependency on setuptools:

https://github.com/adafruit/circup/blob/86ff01c5fb33d130ffb8d9ed3ed144cedb220c03/circup/__init__.py#L23

but it's not named in the `install_requires`

https://github.com/adafruit/circup/blob/86ff01c5fb33d130ffb8d9ed3ed144cedb220c03/setup.py#L25-L34

Alternatively we could migrate to `importlib.resources` (new in Python 3.7, but a backport for 3.6 exists)
https://docs.python.org/3/library/importlib.html#module-importlib.resources

Start by reading circup/__init__.py at the pkg_resources import and setup.py around install_requires. Compare the two options described in the issue: declaring setuptools as a runtime dependency or migrating to importlib.resources. The work is done when a fresh installation no longer raises ModuleNotFoundError and the supported Python versions continue to work.

Written by the indexing model from the issue text.