Integrate Docker Hub and Tekton into Knative Eventing

Knative is a Kubernetes-based platform to deploy and manage serverless workloads. Eventing is a key feature for Serverless Computing. They deliver their information to a specified target to make a whole system interactive. The problem is that every kind of event cannot be treated as the same one in the Knative ecosystem because the shape of each event depends on its sources. Knative Eventing is designed to be consistent with the CloudEvents definition to keep interoperability. To make this happen, the Knative Eventing community already has several kinds of event type definitions such as GitHub, AWS S3, GCP Pub/Sub, etc.
This project aims to add two event types:

• an event source that is able to generate CloudEvents when a new container image is uploaded to Docker Hub.
• another event source that is able to generate CloudEvents on success/failure of Task/Pipeline and every step of a Pipeline created by Tekton CI/CD.

Both components would help application developers focus on developing applications itself and make Serverless Computing more diverse.