For citar support/bugs, you should report on the github issue tracker.
But my guess: you need to install citar-embark, as a while ago, we
moved the embark-related functionality into a separate package. If
it's been a few months since you've updated, that would likely explain
it.
If someone should come acress this thread I can confirm that Bruce's suggestion works. Just install citar-embark and configure it according to the instructions on the github page. Should I add this to the issue tracker as well Bruce?