Add a jules-done label when jules opens a PR

[iHildy]

When Jules is successfully competed a task it will comment something like:

Ready for a review! A [PR](https://github.com/iHildy/jules-task-queue/pull/130) has been created.

We need to detect that and give it a jules-done label so we can make it clear to users in github. Start with the jules.ts file. Also add in jules-done label creation when the repository is connected during onboarding, give it color #e539a6

[google-labs-jules]

Jules is on it. When finished, you will see another comment and be able to review a PR.

[google-labs-jules]

Ready for a review! A PR has been created.