Support for dependsOn

[Willem-J-an]

Hi @EthanJWright,

Decided to create a dedicated issue, and elaborate a bit on the dependsOn feature and how I used it within VS code. Hope this helps if you get around to working on this.

1. Regular dependsOn, to chain multiple tasks linearly. This is the most barebones aspect.
2. Fan in support; a task can depend on multiple tasks. It is possible to define a dummy task that does not do anything but it triggers the two tasks it dependsOn, e.g. starting a server and an emulator or something.
3. Presentation groups; Especially useful when triggering multiple tasks. It is used to indicate the tasks should be visible next to each other. This might make less sense in neovim, than in vscode.

[vansoest]

+1 to have this—I have a chain of tasks used with dependsOn.