slack: Updatescript allow independent updates between linux and macos

latest_linux_version=$(curl -L --silent https://slack.com/downloads/linux | sed -n 's/.*Version \([0-9\.]\+\).*/\1/p')

latest_mac_version=$(curl -L --silent https://slack.com/downloads/mac | sed -n 's/.*Version \([0-9\.]\+\).*/\1/p')

# Double check that the latest mac and linux versions are in sync.

if [[ "$latest_linux_version" != "$latest_mac_version" ]]; then

  echo "the latest linux ($latest_linux_version) and mac ($latest_mac_version) versions are not the same"

  exit 1

fi

nixpkgs="$(git rev-parse --show-toplevel)"

slack_nix="$nixpkgs/pkgs/applications/networking/instant-messengers/slack/default.nix"

nixpkgs_linux_version=$(cat "$slack_nix" | sed -n 's/.*x86_64-linux-version = \"\([0-9\.]\+\)\";.*/\1/p')