Allow changing the stable/unstable status of a file

[BrainStone]

Is your feature request related to a problem? Please describe.
It's quite nice that you can mark versions as unstable, however as time goes by, it can turn out that a unstable version is stable or a version thought to be stable is in fact unstable.

Describe the solution you'd like
It would be much apprechiated if the stable/unstable state of a version could be changed on the page where you can currently change the version description/changelog

Describe alternatives you've considered (optional)
if changing the channel will end up on a different page, the that feature should be there as well.

Additional context
As discussed on the Discord, there are plans to be able to change the channel of a version. It would be nice if that could be changed as well.