New PUMAS tag coming with ML updates

### What is the feature/what would you like to discuss?

We added some emulator code for warm rain accretion a few years ago, but some of it didn't work well, or crashed. @djgagne has updated a PR into PUMAS that should fix these issues. Once that is merged, I'll make a PUMAS tag and issue a PR to CAM to update the external.

This should only impact the ML code, which is an option that is not used in any currently scientifically scrutinized versions of CAM. So, will likely not change answers.

The PR is here if anyone is curious or concerned: https://github.com/ESCOMP/PUMAS/pull/73

### Is there anyone in particular you want to be part of this conversation?

_No response_

### Will this change (regression test) answers?

No

### Will you be implementing this enhancement yourself?

Yes