Add CI/CD to build multi-approver when files under src change

### TL;DR

We need to automate this using GH Actions/Workflows because it's easy to forget to do this.

### Detailed design

```markdown
I'm not sure if we have a good example of this. We can check with the porcupine team to see what their approach is.
```

### Alternatives considered

```markdown

```

### Additional information

_No response_