update

#!/usr/bin/env nix-shell
#! nix-shell -i sh -p nix-prefetch-git jq

url="https://git.c3pb.de/jens/qbar.git"
ref="refs/heads/master"

nix-prefetch-git --rev "$ref" --no-deepClone "$url" | jq --arg ref "$ref" '{ref: $ref} + .' > repo.json