Interactive Tracking Plan Update Support: `typewriter update --interactive`

[colinking]

This issue tracks progress towards adding an interactive variant of typewriter update that allows you to select which updates to apply, if there are multiple.

Currently, when you run typewriter update (or typewriter -- it's the default command), it'll pull down all changes, s.t. your plan.json matches your Tracking Plan from segment.com. However, with large teams, this often pulls in unrelated changes that you have to manually prune from your plan.json.

Ideally, you can select the subset of changes that are relevant to you. I imagine two ways:

• By label ("apply all changes with team:protocols")
• By individual event ("select and apply these 3 events")