Overlay with `update: []` doesn't actually update the spec

Given `spec.yaml`:

```yaml
openapi: 3.1.0
info:
title: "..."
description: "..."
version: 1.0.0

servers:
- url: https://example.com
description: Super secret, don't share!
```

And `overlay.yaml`:

```yaml
overlay: 1.0.0
info:
title: "..."
version: 1.0.0
actions:
- target: $.servers
update: []
```

When running:

```
npx bump-cli@2.9.11 overlay spec.yaml overlay.yaml
```

the resulting spec is:

```yaml
openapi: 3.1.0
info:
title: ...
description: ...
version: 1.0.0
servers:
- url: 'https://example.com'
description: 'Super secret, don''t share!'
```

However, I would expect it to have replaced the `servers` with an empty array