Using collapsible groups

[jakirkham]

For sections in CI that we want to collapse (like installing Conda packages or similar), we might want to use collapsible groups in shell output to improve log navigation.

In conda-forge we do this with a couple shell functions called startgroup and endgroup defined in this script. As a result, we can put steps (like installing Miniconda) in a collapsible group, which appears like so.