Add KinD test verifying the source deploys and becomes ready

## Overview

We recently found that even though build and unit tests had been passing, the receive adapter panicked when it started when you actually deployed the gitlab source. To address this, we should add a KinD test job that will:
1. Install eventing and the gitlab source
2. Create a gitlab source
3. Verify that the source becomes ready

## More info

These resources will likely be helpful while working on this:
- https://github.com/knative/eventing/blob/main/.github/workflows/kind-e2e.yaml
- https://github.com/knative-extensions/reconciler-test
- https://github.com/knative/eventing/tree/main/test/rekt