Update registry.k8s.io/external-dns/external-dns Docker tag to v0.15.1 (#403)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

hack/config/external-dns/kustomization.yaml

@@ -5,7 +5,7 @@ namespace: external-dns
 
 images:
 - name: registry.k8s.io/external-dns/external-dns
-  newTag: v0.15.0
+  newTag: v0.15.1
 
 resources:
 - namespace.yaml