`poetry show --outdated`: also show latest "wanted" version

Issue Kind

Change in current behaviour

Description

poetry show --outdated currently shows two versions for each package: the currently installed version and the highest available version.

It would be nice if poetry would also show the latest "wanted" version, that is, the latest version allowed by version constraints.

For example npm outdated reports

$ npm outdated
Package                           Current   Wanted   Latest [...]
[...]
style-loader                        3.3.3    3.3.4    4.0.0 [...]

Impact

Users can easily see that wanted updates are available even when they are not on the latest release.

For example, consider a project using the latest Django LTS release:

[tool.poetry.dependencies]
[...]
Django = "~4.2.10"

I would like to install patch updates for this, but cannot see when some are available: poetry show --outdated only reports that a new major release (5.x) is available. It would be nice if it would also show newer 4.2.x patch releases.

Workarounds

Run poetry update and check what changed or manually look for updates.

Start at the poetry show --outdated command and trace how it currently determines the installed and highest available versions. Review how the project’s version constraints define the latest allowed version, then verify that the output reports installed, wanted, and latest versions for cases such as Django ~4.2.10.