Add list option to filter out entries that have a newer version available

[MrDRamos]

Description of the new feature / enhancement

I would like to quickly get a list off all installed packages that are outdated before invoking an upgrade.

Proposed technical implementation details

Add a command line option to the list command e.g --outdated that filters the results to only show packages that have a newer version available

[Trenly]

Try winget upgrade without any arguments

[MrDRamos]

Thank you, that does exactly what I was looking for!
I did not see this feature in the documentation.
Personally I still think it more intuitive to get this output by specifying an explicit option, because it makes the users intention clear.

[denelon]

The help isn't clear that running the command without arguments displays a list of packages with available upgrades. We should update the help.

[Trenly]

@denelon - Has this been resolved with the above PR?