version=4
opts="filenamemangle=s/(?:.*\/)?v?([^\/]+)\.tar\.gz/prometheus-alertmanager-$1.tar.gz/,\
      dversionmangle=s/\+ds\d*$//,\
      uversionmangle=s/rc/~rc/" \
  https://github.com/prometheus/alertmanager/tags \
  (?:.*/)?v?(\d[\d\.]*(?:rc\d*)?)\.tar\.gz
