[CI] update setup_miniconda version #1192
Description
The remaining deprecation warnings depend on a new release of [setup_miniconda](https://github.com/conda-incubator/setup-miniconda/issues/248). @samuelgarcia Do you prefer to merge these updates already now or wait until we can update also setup-miniconda?
Originally posted by @JuliaSprenger in #1191 (comment)