Personally I'd be somewhat inclined to do this in a hover rather than an inlay hint, but debatable.

Not sure what a coherent argument would look like, but I would argue something like:

• Inlay hints are good for things you always want to see that provide missing context
• Inlay hints are often supposed to be something you can "accept", which adds the content into the buffer. But the inlay hint here isn't valid syntax!
• Hovers are good for extra information that you want when you are focussing your attention on a specific thing. I think I mostly want to know package versions when I'm thinking about a specific package dependency, so I think that suits hovers a bit more?