Propellor seems inaccessible to me.
The contribution workflow is based on emails or unstructured todo wiki subpages. It is unclear where to get help.
I suggest you switch to using https://gitlab.haskell.org for example
Getting contributions in open source is about how accessible your project is. That includes not only codebase, but especially workflow. I also barely see anyone respond to propellor topics on #haskell freenode.
We use propellor at work and I'm already wondering if ansible would have been a better choice.