license-check: add BSD-3-Clause to allow-list

We're using dependencies with this license in many places, and it should
be ok to use.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

.wwhrd.yml

@@ -4,6 +4,7 @@ blacklist:
 
 whitelist:
   - Apache-2.0
+  - BSD-3-Clause
   - FreeBSD
   - LGPL-3.0
   - MIT
@@ -26,4 +27,4 @@ exceptions:
   - k8s.io/metrics/pkg/client/clientset_generated/clientset # Unknown
   - k8s.io/metrics/pkg/client/clientset_generated/clientset/scheme # Unknown
   - k8s.io/metrics/pkg/client/clientset_generated/clientset/typed/metrics/v1alpha1 # Unknown
-  - k8s.io/metrics/pkg/client/clientset_generated/clientset/typed/metrics/v1beta1 # Unknown
+  - k8s.io/metrics/pkg/client/clientset_generated/clientset/typed/metrics/v1beta1 # Unknown