Support `workflow_run` event type in GitHub Actions deploy

### What problem are you trying to solve?

Among the available event types (https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows), Deno Deploy only support `pull_request`, `push`, `schedule`, and `workflow_dispatch` now to trigger the deployment process.

There are some reasonable use cases to use other event types - in particular `workflow_run`, where for example another workflow creates and pushes a file to the repo, and then `workflow_run` event is fired to trigger the deployment process.

### Describe the solution you'd like

We can start the deployment process by `workflow_run` event. Something like:

```yaml
on:
workflow_run:
workflows: [Do something]
types:
- completed
```

### Describe alternatives you've considered

N/A

### Documentation, Adoption, Migration Strategy

https://discord.com/channels/684898665143206084/826085979344470037/1225472297079537764