Automatically check for a new update of mcman

[Senth]

Is your feature request related to a problem? Please describe.

It's hard to know when there's a new update to minecraft-mod-manager.

Describe the solution you'd like

It would be good if it automatically told you through GUI and CLI that a new version is available.

Describe alternatives you've considered

A clear and concise description of any alternative solutions or features you've considered.

Additional context

For Windows or even all platforms, it would also be good if it could automatically update itself. Another feature.