`import cornish` fails when installed from `pip` or source

[sweverett]

Hello - I was hoping to try out cornish at the recommendation of Eric Huff. I can install successfully from either pip or source on a fresh conda env, but in either case I get the following:

python -c "import cornish"
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/Users/sweveret/miniconda3/envs/astro/lib/python3.9/site-packages/cornish/__init__.py", line 7, in <module>
    from .channel.ast_channel import ASTChannel
ModuleNotFoundError: No module named 'cornish.channel'

I asked Eric what version he has installed on a previously used env and it was v1.1. I made a new env that built from source on the v1.1 tag and have the same outcome. I can do some more digging later in case I missed something obvious, but I thought I would flag it.