Unable to implement multiple branches with `forkTask`

Hi 👋

I think that perhaps the implementation of [forkTask](https://github.com/conductor-oss/javascript-sdk/blob/main/src/sdk/builders/tasks/forkJoin.ts) limits the developer to creating a single branch.

[The fork example in the docs](https://docs.conductor-oss.org/documentation/configuration/workflowdef/operators/fork-task.html) shows that `forkTasks` should be `List[List[Task]]` but I believe the signature here limits this to `[List[Task]]` ( note this is an array with a single item, not a `List[]` ).

Am I reading this correct? I can't seem to get `forkTask()` to create the output I'm after, but not sure if that's user error or an issue with the library.

In the meantime I'm implementing this manually.

Commencez dans src/sdk/builders/tasks/forkJoin.ts et comparez la signature et la structure générée de forkTask avec l’exemple lié de la documentation Conductor sur fork-task. Reproduisez le cas comportant plusieurs branches, puis vérifiez que le builder accepte List[List[Task]] et produit la définition de workflow attendue.

Rédigé par le modèle d'indexation à partir du texte de l'issue.