feat: visually show if plugins need to be updated

[mamaraddio]

[wintermi]

Visually this is great.

I do have a couple of comments:

Running a zap update with this change took longer than just running the update of all plugins.

In my opinion I think that this should become a new command/option, say zap update-check or zap update --check which could then allow for the zap update-all or zap update --all PR we received.

If the check was fast and you could not see each plugin being checked, I would say let's just do it.

Should we ask the discord channel which they would prefer?

[mamaraddio]

I think is more convenient to leave the two PRs, #123 and this, separated.

I've taken a look at #123 and I'll propose some changes to that.

I think zap have to continue to behave like now, the zap update command has to be "interactive" but it can accept an optional argument like zap update all or zap update supercharge and so on.

For what concern this PR, your commits make the codebase simpler but lose the "Local ahead remote" information that can look a bit stupid for the majority of the users, and actually nothing serious, but maybe who is participating to the development of a plugin could appreciate it. To avoid to call the same git command twice, it could be called once and stored in a variable.

I agree that we could submit this discussion on the Discord channel and to @ChristianChiarulli and leave the users chose what direction we should follow.

[mamaraddio]

Last commit leads to the following by using git status -uno as suggested by @wintermi