[Question] How to let list items "appear" with *.mdx

(edit: this should have a "Question"-Tag, but I can't assign it)

### Question

I am running my slides from MDX and have trouble figuring out how to let items appear one by one.

#### Example
```
- this should appear first
- then this on the next ArrowRight press
- then this ...

---

- then the next slide should show

```

### Background Info/Attempts

#### Attempts
I tried it on the stable release, but while trying to figure things out, I also looked into the current beta (Branch `main-7`) and there is something that looks [like what I want.](https://github.com/FormidableLabs/spectacle/blob/cdd64740123b707e88ec79479ea4f9970792a9b5/src/components/markdown/markdown.js#L69) Unfortunately I can't get this working locally.

#### Tried custom solution
Not finding a solution in your source code (while still thinking it might exist), I created a Component to work with [(Link to code)](https://github.com/badabam/slides2021/blob/main/src/components/StepList.js), but it only works on the current stable release and breaks in `main-7`. It looks like you changed the way you render the slides (i.e. pages).

### Help needed

I would love to hear from you to get this figured out – in any way you prefer. Could be a thread here, mail, zoom/google/teams-call. If it helps, here is [the Repo I am working on](https://github.com/badabam/slides2021).