Issues with mix hex.outdated Command and Dependency Updates in Elixir

An Elixir developer, marcmerrillofficial, has run into a puzzling problem with dependency management. Using the `mix hex.outdated` command, they identified that updates are possible for the Phoenix and PlugCowboy dependencies in their project. However, when `mix deps.update --all` is executed to update all dependencies, no updates are performed for these particular packages despite the availability of the newer versions. The developer is seeking to understand the underlying cause of this discrepancy—whether it's a mistake on their part or a lack of information about the dependency update process. This may highlight an area where Elixir's package management tooling can offer more clarity or guidance to developers when updates are not proceeding as indicated by the outdated command.