Mention Mamba as an alternative package manager instead of conda

[jauy123]

How could the content be improved?

Add a reference to the mamba package manager to ./learners/setup.md as an alternative to conda and potentially replace all instances of the default anaconda repository in each yaml file to conda-forge instead.

A general trend I been noticing is that scientific computing as a trend is moving away from anaconda (due to their license changes in 2024) and moving towards alternative implementations such as mamba (which is a C++ implementation of conda) .

At Arizona State University, my home institution, mamba is a mature enough to the extent that python package management on our local HPC nodes is entirely done with mamba as a systemwide backend.

Which part of the content does your suggestion apply to?

https://datacarpentry.github.io/astronomy-python/#software