curl is needed for updateTaxonomy.sh even though --only-build flag is set

[FynnFreyer]

Not sure if this is wanted, but it is inconvenient for a project I'm working on, where I try to create a minimal container and don't want to go through the hassle of installing curl just for this and uninstalling it afterwards.

If you decide to change this, I have forked the repository and added an if statement to check whether updateTaxonomy.sh runs with the --only-build flag passed. In which case, I think the check for curl being installed is unnecessary. I will send the Pull Request soon.

Feel free to ignore this if it's by design, rather than no one actually having a problem with it as yet.