Installation on cheyenne requires change to ilamb-sysmpi.yml

[olyson]

Just documenting this here.
I use the following steps to install ILAMB on the NCAR machine cheyenne:
git clone https://github.com/rubisco-sfa/ILAMB.git ./ilamb_standalone
cd ilamb_standalone/
conda env create -f ilamb-sysmpi.yml
conda activate ilamb
pip install ./

In order for this to be successful, I have to make the following change to ilamb-sysmpi.yml:

diff --git a/ilamb-sysmpi.yml b/ilamb-sysmpi.yml
index 5c0a5d4..2dab295 100644
--- a/ilamb-sysmpi.yml
+++ b/ilamb-sysmpi.yml
@@ -19,5 +19,6 @@ dependencies:

--- cf_units
--- cython
--- psutil
+++ --- pip
--- pip:
--- mpi4py

Otherwise, I get an endless number of messages like this:

Warning: you have pip-installed dependencies in your environment file, but you do not list pip itself as one of your conda dependencies. Conda may not use the correct pip to install your packages, and they may end up in the wrong place. Please add an explicit pip dependency. I'm adding one for you, but still nagging you.

I don't know if this is machine dependent or something specific with my environment. Not a big deal since I can install and run ILAMB successfully with this change.