Add support for branching in `Workflow`s

[vachillo]

• [x] I have read and agree to the contributing guidelines.

Is your feature request related to a problem? Please describe. I am trying to build a workflow where I want to conditionally run different Tasks based on the parent's output.

Describe the solution you'd like I want to be able to conditionally branch to different Tasks depending on the output of the parent.

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

Additional context Add any other context or screenshots about the feature request here.