Support for filtering namespaces?

I see this listed in the roadmap, but is the feature specified anywhere?

I want to request support for some kind of wildcard.

The simple `*` blobs supported by kyverno matches would be sufficient for my needs:

```yaml
allowedNamespaces: cluster-*
```

As would a full regex:

```yaml
allowedNamespaces: somecluster|someprefix.*
```