`gleam add` should warn if an old version is added

[winterqt]

When a user wants to add the latest version of a dependency, if version resolution results in an older version being added, the user should be made aware.

See this message and its surrounding discussion for an example of where this would have been made a bit clearer, as version resolution resulted in Gleam adding a version of Birdie that didn’t depend on Glance.

This should only fire when an explicit bound is not specified.

[lpil]

What's the definition of old version here? Lots of old releases are fine, I'm not sure how we would identify the specific situation you highlight here.