Nice. It is great to see native lightweight opensource (I hope it is considering that someone said that there is no license file yet) solutions hit this space. For what it's worth, I have built something similar to this but for Java programming language. You can find it here -> https://github.com/americanexpress/unify-flowret. My reason for building something like this was that the product market is just too unwieldy to work with and has multiple layers of complexity which most of the time can be done away with. Just my opinion.
On a side note, you will at some point in time have to deal with multi version workflows. I know that this is one feature that limits wide adoption of an orchestrator.