Having a look at this PR to see if it could help with a problem we're having.

Are you sure that `ref` always points to `ref/heads/`? AFAIK if you push tags to GitHub then `ref` could refer to `refs/tags/`. An actual event we see can look like:

```json
{
  "ref": "refs/tags/[TAG]",
  "after": "[SAH1]",
  "before": "0000000000000000000000000000000000000000",
  "created": true,
  "deleted": false,
  "forced": true,
  "compare": "https://github.com/[ORG]/[REPO]/compare/[TAG]",
  "commits": [],
 ...
```

Or am I misunderstanding where `ref` comes from?