Homestead.yaml mongodb: true not installing mongo database

After struggling with this for a couple hours, I found it (and it was staring me in the face the whole time). The syntax changed in version 9.0.0 and the documentation hasn't been updated. The new syntax is:

features:
    - mongodb: true

Try adding that to the config.

how did you figured it out?

It was well hidden...

I eventually found it in the Git laravel/homestead 9.0.0 release notes here: https://github.com/laravel/homestead/releases/tag/v9.0.0