[Proposal]: Using CloudEvents for better compatibility

### Is your feature request related to a problem? Please describe.

It's not related to a problem, but rather for increasing compatibility with existing systems.

### Describe the solution you'd like

Currently, the protocol mentioning the following events: `TaskArtifactUpdateEvent` and `TaskStatusUpdateEvent`.

I would like the available events to follow the convention of CloudEvents spec for better compatibility with existing softwares.

CloudEvents: https://github.com/cloudevents/spec

This is just an initial discussion whether that's a good idea or not.

### Code of Conduct

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