Is there any way to create a yaml header variable and use it within markdown?

**Operation System**: (`Windows` or `Linux` or `MacOS`)

**DocFX Version Used**:

2.50

**Template used**: (`default` or `statictoc` or contain custom template)

custom

**Steps to Reproduce**:

I just want to be able to define variables, both globally and hopefully within a yaml header and then reference them within the markdown file.

For example, in an md file I might have:

```
---
uid: download/4.8.0-beta00008
currentVersion: 4.8.0-beta00008
---
```

Then I want to be able to use the `currentVersion` variable/front-matter/yaml-header in my markdown file.

Is this possible? and can this also be achieved by specifying global variables in the docfx.json file?

Thanks