used to fetch chrom.sizes information from UCSC for the given <db>
https://anaconda.org/bioconda/ucsc-fetchchromsizes/badges/version.svg
https://anaconda.org/bioconda/ucsc-fetchchromsizes/badges/latest_release_date.svg
https://anaconda.org/bioconda/ucsc-fetchchromsizes/badges/latest_release_relative_date.svg
https://anaconda.org/bioconda/ucsc-fetchchromsizes/badges/platforms.svg
https://anaconda.org/bioconda/ucsc-fetchchromsizes/badges/license.svg
https://anaconda.org/bioconda/ucsc-fetchchromsizes/badges/downloads.svg