Background
With render_doc_url, the version in doc URLs takes into account the patch version:
https://github.com/canonical/craft-application/blob/fb5998d97b1cccd068843615047de9c75aeb1cc4/craft_application/util/docs.py
When we move to minor-only RTD versions, these paths won't be available anymore.
Request
In alignment with our near-term plans of only publishing docs as minor versions, this function should substitute the minor version of the built app.