mirror an upstream conda channel to a local directory
https://anaconda.org/conda-forge/conda-mirror/badges/version.svg
https://anaconda.org/conda-forge/conda-mirror/badges/latest_release_date.svg
https://anaconda.org/conda-forge/conda-mirror/badges/latest_release_relative_date.svg
https://anaconda.org/conda-forge/conda-mirror/badges/platforms.svg
https://anaconda.org/conda-forge/conda-mirror/badges/license.svg
https://anaconda.org/conda-forge/conda-mirror/badges/downloads.svg